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          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_AssetAllocationRiskMember" xml:lang="en-US">Asset Allocation Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_AssetAllocationRiskMember" xlink:to="lab_cik0001170311_AssetAllocationRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_CaliforniaStateSpecificRiskMember" xlink:label="loc_cik0001170311_CaliforniaStateSpecificRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_CaliforniaStateSpecificRiskMember" xml:lang="en-US">California State-Specific Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_CaliforniaStateSpecificRiskMember" xlink:to="lab_cik0001170311_CaliforniaStateSpecificRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_CallRiskMember" xlink:label="loc_cik0001170311_CallRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_CallRiskMember" xml:lang="en-US">Call Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_CallRiskMember" xlink:to="lab_cik0001170311_CallRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_CertainAffiliationsMember" xlink:label="loc_cik0001170311_CertainAffiliationsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_CertainAffiliationsMember" xml:lang="en-US">Certain Affiliations [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_CertainAffiliationsMember" xlink:to="lab_cik0001170311_CertainAffiliationsMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_ConfidentialInformationAccessRiskMember" xlink:label="loc_cik0001170311_ConfidentialInformationAccessRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_ConfidentialInformationAccessRiskMember" xml:lang="en-US">Confidential Information Access Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_ConfidentialInformationAccessRiskMember" xlink:to="lab_cik0001170311_ConfidentialInformationAccessRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_CounterpartyRiskMember" xlink:label="loc_cik0001170311_CounterpartyRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_CounterpartyRiskMember" xml:lang="en-US">Counterparty Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_CounterpartyRiskMember" xlink:to="lab_cik0001170311_CounterpartyRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_CreditDefaultSwapsRiskMember" xlink:label="loc_cik0001170311_CreditDefaultSwapsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_CreditDefaultSwapsRiskMember" xml:lang="en-US">Credit Default Swaps Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_CreditDefaultSwapsRiskMember" xlink:to="lab_cik0001170311_CreditDefaultSwapsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_CreditRisk1Member" xlink:label="loc_cik0001170311_CreditRisk1Member" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_CreditRisk1Member" xml:lang="en-US">Credit Risk 1 [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_CreditRisk1Member" xlink:to="lab_cik0001170311_CreditRisk1Member" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_CyberSecurityRiskMember" xlink:label="loc_cik0001170311_CyberSecurityRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_CyberSecurityRiskMember" xml:lang="en-US">Cyber Security Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_CyberSecurityRiskMember" xlink:to="lab_cik0001170311_CyberSecurityRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_DerivativesRiskMember" xlink:label="loc_cik0001170311_DerivativesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_DerivativesRiskMember" xml:lang="en-US">Derivatives Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_DerivativesRiskMember" xlink:to="lab_cik0001170311_DerivativesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_DistributionRateRiskMember" xlink:label="loc_cik0001170311_DistributionRateRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_DistributionRateRiskMember" xml:lang="en-US">Distribution Rate Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_DistributionRateRiskMember" xlink:to="lab_cik0001170311_DistributionRateRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_FocusedInvestmentRiskMember" xlink:label="loc_cik0001170311_FocusedInvestmentRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_FocusedInvestmentRiskMember" xml:lang="en-US">Focused Investment Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_FocusedInvestmentRiskMember" xlink:to="lab_cik0001170311_FocusedInvestmentRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_HighYieldSecuritiesRiskMember" xlink:label="loc_cik0001170311_HighYieldSecuritiesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_HighYieldSecuritiesRiskMember" xml:lang="en-US">High Yield Securities Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_HighYieldSecuritiesRiskMember" xlink:to="lab_cik0001170311_HighYieldSecuritiesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_IllinoisStatespecificRiskMember" xlink:label="loc_cik0001170311_IllinoisStatespecificRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_IllinoisStatespecificRiskMember" xml:lang="en-US">Illinois State-Specific Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_IllinoisStatespecificRiskMember" xlink:to="lab_cik0001170311_IllinoisStatespecificRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_InflationDeflationRiskMember" xlink:label="loc_cik0001170311_InflationDeflationRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_InflationDeflationRiskMember" xml:lang="en-US">Inflation/Deflation Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_InflationDeflationRiskMember" xlink:to="lab_cik0001170311_InflationDeflationRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_InsuranceLinkedAndOtherInstrumentsRiskMember" xlink:label="loc_cik0001170311_InsuranceLinkedAndOtherInstrumentsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_InsuranceLinkedAndOtherInstrumentsRiskMember" xml:lang="en-US">Insurance-Linked and Other Instruments Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_InsuranceLinkedAndOtherInstrumentsRiskMember" xlink:to="lab_cik0001170311_InsuranceLinkedAndOtherInstrumentsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_InsuranceRiskMember" xlink:label="loc_cik0001170311_InsuranceRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_InsuranceRiskMember" xml:lang="en-US">Insurance Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_InsuranceRiskMember" xlink:to="lab_cik0001170311_InsuranceRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_IssuerRiskMember" xlink:label="loc_cik0001170311_IssuerRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_IssuerRiskMember" xml:lang="en-US">Issuer Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_IssuerRiskMember" xlink:to="lab_cik0001170311_IssuerRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_LeverageRiskMember" xlink:label="loc_cik0001170311_LeverageRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_LeverageRiskMember" xml:lang="en-US">Leverage Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_LeverageRiskMember" xlink:to="lab_cik0001170311_LeverageRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_LiquidityRiskMember" xlink:label="loc_cik0001170311_LiquidityRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_LiquidityRiskMember" xml:lang="en-US">Liquidity Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_LiquidityRiskMember" xlink:to="lab_cik0001170311_LiquidityRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_LoanOriginationRiskMember" xlink:label="loc_cik0001170311_LoanOriginationRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_LoanOriginationRiskMember" xml:lang="en-US">Loan Origination Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_LoanOriginationRiskMember" xlink:to="lab_cik0001170311_LoanOriginationRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" xlink:label="loc_cik0001170311_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" xml:lang="en-US">Loans and Other Indebtedness; Loan Acquisitions, Participations and Assignments Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" xlink:to="lab_cik0001170311_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_ManagementRiskMember" xlink:label="loc_cik0001170311_ManagementRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_ManagementRiskMember" xml:lang="en-US">Management Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_ManagementRiskMember" xlink:to="lab_cik0001170311_ManagementRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_MarketDiscountRiskMember" xlink:label="loc_cik0001170311_MarketDiscountRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_MarketDiscountRiskMember" xml:lang="en-US">Market Discount Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_MarketDiscountRiskMember" xlink:to="lab_cik0001170311_MarketDiscountRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_MarketDisruptionsRiskMember" xlink:label="loc_cik0001170311_MarketDisruptionsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_MarketDisruptionsRiskMember" xml:lang="en-US">Market Disruptions Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_MarketDisruptionsRiskMember" xlink:to="lab_cik0001170311_MarketDisruptionsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_MarketRiskMember" xlink:label="loc_cik0001170311_MarketRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_MarketRiskMember" xml:lang="en-US">Market Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_MarketRiskMember" xlink:to="lab_cik0001170311_MarketRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_MortgageRelatedAndOtherAssetBackedSecuritiesRiskMember" xlink:label="loc_cik0001170311_MortgageRelatedAndOtherAssetBackedSecuritiesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_MortgageRelatedAndOtherAssetBackedSecuritiesRiskMember" xml:lang="en-US">Mortgage-Related and Other Asset-Backed Instruments Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_MortgageRelatedAndOtherAssetBackedSecuritiesRiskMember" xlink:to="lab_cik0001170311_MortgageRelatedAndOtherAssetBackedSecuritiesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_MortgageRelatedDerivativeInstrumentsRiskMember" xlink:label="loc_cik0001170311_MortgageRelatedDerivativeInstrumentsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_MortgageRelatedDerivativeInstrumentsRiskMember" xml:lang="en-US">Mortgage-Related Derivative Instruments Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_MortgageRelatedDerivativeInstrumentsRiskMember" xlink:to="lab_cik0001170311_MortgageRelatedDerivativeInstrumentsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_MunicipalBondRiskMember" xlink:label="loc_cik0001170311_MunicipalBondRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_MunicipalBondRiskMember" xml:lang="en-US">Municipal Bond Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_MunicipalBondRiskMember" xlink:to="lab_cik0001170311_MunicipalBondRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_MunicipalProjectHousingRelatedRiskMember" xlink:label="loc_cik0001170311_MunicipalProjectHousingRelatedRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_MunicipalProjectHousingRelatedRiskMember" xml:lang="en-US">Municipal Project Housing-Related Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_MunicipalProjectHousingRelatedRiskMember" xlink:to="lab_cik0001170311_MunicipalProjectHousingRelatedRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_MunicipalProjectSpecificRiskMember" xlink:label="loc_cik0001170311_MunicipalProjectSpecificRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_MunicipalProjectSpecificRiskMember" xml:lang="en-US">Municipal Project-Specific Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_MunicipalProjectSpecificRiskMember" xlink:to="lab_cik0001170311_MunicipalProjectSpecificRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_NewYorkStateSpecificRiskMember" xlink:label="loc_cik0001170311_NewYorkStateSpecificRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_NewYorkStateSpecificRiskMember" xml:lang="en-US">New York State-Specific Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_NewYorkStateSpecificRiskMember" xlink:to="lab_cik0001170311_NewYorkStateSpecificRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_OperationalRiskMember" xlink:label="loc_cik0001170311_OperationalRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_OperationalRiskMember" xml:lang="en-US">Operational Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_OperationalRiskMember" xlink:to="lab_cik0001170311_OperationalRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_OtherInvestmentCompaniesRiskMember" xlink:label="loc_cik0001170311_OtherInvestmentCompaniesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_OtherInvestmentCompaniesRiskMember" xml:lang="en-US">Other Investment Companies Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_OtherInvestmentCompaniesRiskMember" xlink:to="lab_cik0001170311_OtherInvestmentCompaniesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_PortfolioTurnoverRiskMember" xlink:label="loc_cik0001170311_PortfolioTurnoverRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_PortfolioTurnoverRiskMember" xml:lang="en-US">Portfolio Turnover Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_PortfolioTurnoverRiskMember" xlink:to="lab_cik0001170311_PortfolioTurnoverRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_PotentialConflictsOfInterestRiskMember" xlink:label="loc_cik0001170311_PotentialConflictsOfInterestRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_PotentialConflictsOfInterestRiskMember" xml:lang="en-US">Potential Conflicts of Interest Risk &#8212; Allocation of Investment Opportunities [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_PotentialConflictsOfInterestRiskMember" xlink:to="lab_cik0001170311_PotentialConflictsOfInterestRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_PrivacyAndDataSecurityRiskMember" xlink:label="loc_cik0001170311_PrivacyAndDataSecurityRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_PrivacyAndDataSecurityRiskMember" xml:lang="en-US">Privacy and Data Security Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_PrivacyAndDataSecurityRiskMember" xlink:to="lab_cik0001170311_PrivacyAndDataSecurityRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_PrivatePlacementAndRestrictedSecuritiesRiskMember" xlink:label="loc_cik0001170311_PrivatePlacementAndRestrictedSecuritiesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_PrivatePlacementAndRestrictedSecuritiesRiskMember" xml:lang="en-US">Private Placement and Restricted Securities Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_PrivatePlacementAndRestrictedSecuritiesRiskMember" xlink:to="lab_cik0001170311_PrivatePlacementAndRestrictedSecuritiesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_PuertoRicoSpecificRiskMember" xlink:label="loc_cik0001170311_PuertoRicoSpecificRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_PuertoRicoSpecificRiskMember" xml:lang="en-US">Puerto Rico-Specific Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_PuertoRicoSpecificRiskMember" xlink:to="lab_cik0001170311_PuertoRicoSpecificRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_RegulatoryChangesRiskMember" xlink:label="loc_cik0001170311_RegulatoryChangesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_RegulatoryChangesRiskMember" xml:lang="en-US">Regulatory Changes Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_RegulatoryChangesRiskMember" xlink:to="lab_cik0001170311_RegulatoryChangesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_RegulatoryRiskMember" xlink:label="loc_cik0001170311_RegulatoryRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_RegulatoryRiskMember" xml:lang="en-US">Regulatory Risk &#8212; Commodity Pool Operator [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_RegulatoryRiskMember" xlink:to="lab_cik0001170311_RegulatoryRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_ReinvestmentRiskMember" xlink:label="loc_cik0001170311_ReinvestmentRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_ReinvestmentRiskMember" xml:lang="en-US">Reinvestment Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_ReinvestmentRiskMember" xlink:to="lab_cik0001170311_ReinvestmentRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_RepurchaseAgreementsRiskMember" xlink:label="loc_cik0001170311_RepurchaseAgreementsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_RepurchaseAgreementsRiskMember" xml:lang="en-US">Repurchase Agreements Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_RepurchaseAgreementsRiskMember" xlink:to="lab_cik0001170311_RepurchaseAgreementsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_SecuritiesLendingRiskMember" xlink:label="loc_cik0001170311_SecuritiesLendingRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_SecuritiesLendingRiskMember" xml:lang="en-US">Securities Lending Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_SecuritiesLendingRiskMember" xlink:to="lab_cik0001170311_SecuritiesLendingRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_SeriesOneMember" xlink:label="loc_cik0001170311_SeriesOneMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_SeriesOneMember" xml:lang="en-US">Series One [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_cik0001170311_SeriesOneMember" xml:lang="en-US">Series 2054 [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_SeriesOneMember" xlink:to="lab_cik0001170311_SeriesOneMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_SeriesTwoMember" xlink:label="loc_cik0001170311_SeriesTwoMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_SeriesTwoMember" xml:lang="en-US">Series Two [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_cik0001170311_SeriesTwoMember" xml:lang="en-US">Series 2054-A [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_SeriesTwoMember" xlink:to="lab_cik0001170311_SeriesTwoMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_ShortExposureRiskMember" xlink:label="loc_cik0001170311_ShortExposureRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_ShortExposureRiskMember" xml:lang="en-US">Short Exposure Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_ShortExposureRiskMember" xlink:to="lab_cik0001170311_ShortExposureRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_StructuredInvestmentsRiskMember" xlink:label="loc_cik0001170311_StructuredInvestmentsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_StructuredInvestmentsRiskMember" xml:lang="en-US">Structured Investments Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_StructuredInvestmentsRiskMember" xlink:to="lab_cik0001170311_StructuredInvestmentsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_TaxRiskMember" xlink:label="loc_cik0001170311_TaxRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_TaxRiskMember" xml:lang="en-US">Tax Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_TaxRiskMember" xlink:to="lab_cik0001170311_TaxRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_UsGovernmentSecuritiesRiskMember" xlink:label="loc_cik0001170311_UsGovernmentSecuritiesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_UsGovernmentSecuritiesRiskMember" xml:lang="en-US">U.S. Government Securities Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_UsGovernmentSecuritiesRiskMember" xlink:to="lab_cik0001170311_UsGovernmentSecuritiesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_ValuationRiskMember" xlink:label="loc_cik0001170311_ValuationRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_ValuationRiskMember" xml:lang="en-US">Valuation Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_ValuationRiskMember" xlink:to="lab_cik0001170311_ValuationRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_ZeroCouponBondStepUpsandPaymentInKindSecuritiesRiskMember" xlink:label="loc_cik0001170311_ZeroCouponBondStepUpsandPaymentInKindSecuritiesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_ZeroCouponBondStepUpsandPaymentInKindSecuritiesRiskMember" xml:lang="en-US">Zero-Coupon Bond, Step-Ups and Payment-In-Kind Securities Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_ZeroCouponBondStepUpsandPaymentInKindSecuritiesRiskMember" xlink:to="lab_cik0001170311_ZeroCouponBondStepUpsandPaymentInKindSecuritiesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_ArpsMember" xlink:label="loc_cik0001170311_ArpsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_ArpsMember" xml:lang="en-US">ARPS [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_ArpsMember" xlink:to="lab_cik0001170311_ArpsMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_CommonSharesMember" xlink:label="loc_cik0001170311_CommonSharesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_CommonSharesMember" xml:lang="en-US">Common Shares [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_CommonSharesMember" xlink:to="lab_cik0001170311_CommonSharesMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_PreferredSharesMember" xlink:label="loc_cik0001170311_PreferredSharesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_PreferredSharesMember" xml:lang="en-US">Preferred Shares [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_PreferredSharesMember" xlink:to="lab_cik0001170311_PreferredSharesMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170311-20251231.xsd#cik0001170311_RvmtpMember" xlink:label="loc_cik0001170311_RvmtpMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170311_RvmtpMember" xml:lang="en-US">RVMTP [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170311_RvmtpMember" xlink:to="lab_cik0001170311_RvmtpMember" />
        </link:labelLink>
      </link:linkbase>
    </appinfo>
  </annotation>
  <import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
  <import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" />
  <import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" />
  <import namespace="http://xbrl.sec.gov/dei/2025" schemaLocation="https://xbrl.sec.gov/dei/2025/dei-2025.xsd" />
  <import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd" />
  <import namespace="http://xbrl.sec.gov/cef/2025" schemaLocation="https://xbrl.sec.gov/cef/2025/cef-2025.xsd" />
  <import namespace="http://xbrl.sec.gov/cef-pre/2025" schemaLocation="https://xbrl.sec.gov/cef/2025/cef-2025_pre.xsd" />
  <element name="RvmtpMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_RvmtpMember" substitutionGroup="xbrli:item" />
  <element name="ArpsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_ArpsMember" substitutionGroup="xbrli:item" />
  <element name="AdditionalRisksAssociatedWithTheFundsPreferredSharesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_AdditionalRisksAssociatedWithTheFundsPreferredSharesMember" substitutionGroup="xbrli:item" />
  <element name="CaliforniaStateSpecificRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_CaliforniaStateSpecificRiskMember" substitutionGroup="xbrli:item" />
  <element name="AssetAllocationRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_AssetAllocationRiskMember" substitutionGroup="xbrli:item" />
  <element name="AntiTakeoverProvisionsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_AntiTakeoverProvisionsMember" substitutionGroup="xbrli:item" />
  <element name="AmtBondsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_AmtBondsRiskMember" substitutionGroup="xbrli:item" />
  <element name="InsuranceRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_InsuranceRiskMember" substitutionGroup="xbrli:item" />
  <element name="InsuranceLinkedAndOtherInstrumentsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_InsuranceLinkedAndOtherInstrumentsRiskMember" substitutionGroup="xbrli:item" />
  <element name="InflationDeflationRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_InflationDeflationRiskMember" substitutionGroup="xbrli:item" />
  <element name="IllinoisStatespecificRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_IllinoisStatespecificRiskMember" substitutionGroup="xbrli:item" />
  <element name="HighYieldSecuritiesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_HighYieldSecuritiesRiskMember" substitutionGroup="xbrli:item" />
  <element name="FocusedInvestmentRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_FocusedInvestmentRiskMember" substitutionGroup="xbrli:item" />
  <element name="DistributionRateRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_DistributionRateRiskMember" substitutionGroup="xbrli:item" />
  <element name="DerivativesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_DerivativesRiskMember" substitutionGroup="xbrli:item" />
  <element name="CyberSecurityRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_CyberSecurityRiskMember" substitutionGroup="xbrli:item" />
  <element name="CreditRisk1Member" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_CreditRisk1Member" substitutionGroup="xbrli:item" />
  <element name="CreditDefaultSwapsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_CreditDefaultSwapsRiskMember" substitutionGroup="xbrli:item" />
  <element name="CounterpartyRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_CounterpartyRiskMember" substitutionGroup="xbrli:item" />
  <element name="ConfidentialInformationAccessRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_ConfidentialInformationAccessRiskMember" substitutionGroup="xbrli:item" />
  <element name="CertainAffiliationsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_CertainAffiliationsMember" substitutionGroup="xbrli:item" />
  <element name="CallRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_CallRiskMember" substitutionGroup="xbrli:item" />
  <element name="ZeroCouponBondStepUpsandPaymentInKindSecuritiesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_ZeroCouponBondStepUpsandPaymentInKindSecuritiesRiskMember" substitutionGroup="xbrli:item" />
  <element name="ValuationRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_ValuationRiskMember" substitutionGroup="xbrli:item" />
  <element name="UsGovernmentSecuritiesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_UsGovernmentSecuritiesRiskMember" substitutionGroup="xbrli:item" />
  <element name="TaxRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_TaxRiskMember" substitutionGroup="xbrli:item" />
  <element name="StructuredInvestmentsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_StructuredInvestmentsRiskMember" substitutionGroup="xbrli:item" />
  <element name="ShortExposureRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_ShortExposureRiskMember" substitutionGroup="xbrli:item" />
  <element name="SecuritiesLendingRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_SecuritiesLendingRiskMember" substitutionGroup="xbrli:item" />
  <element name="RepurchaseAgreementsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_RepurchaseAgreementsRiskMember" substitutionGroup="xbrli:item" />
  <element name="ReinvestmentRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_ReinvestmentRiskMember" substitutionGroup="xbrli:item" />
  <element name="RegulatoryRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_RegulatoryRiskMember" substitutionGroup="xbrli:item" />
  <element name="RegulatoryChangesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_RegulatoryChangesRiskMember" substitutionGroup="xbrli:item" />
  <element name="PuertoRicoSpecificRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_PuertoRicoSpecificRiskMember" substitutionGroup="xbrli:item" />
  <element name="PrivatePlacementAndRestrictedSecuritiesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_PrivatePlacementAndRestrictedSecuritiesRiskMember" substitutionGroup="xbrli:item" />
  <element name="PrivacyAndDataSecurityRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_PrivacyAndDataSecurityRiskMember" substitutionGroup="xbrli:item" />
  <element name="PotentialConflictsOfInterestRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_PotentialConflictsOfInterestRiskMember" substitutionGroup="xbrli:item" />
  <element name="PortfolioTurnoverRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_PortfolioTurnoverRiskMember" substitutionGroup="xbrli:item" />
  <element name="OtherInvestmentCompaniesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_OtherInvestmentCompaniesRiskMember" substitutionGroup="xbrli:item" />
  <element name="OperationalRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_OperationalRiskMember" substitutionGroup="xbrli:item" />
  <element name="NewYorkStateSpecificRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_NewYorkStateSpecificRiskMember" substitutionGroup="xbrli:item" />
  <element name="MunicipalProjectSpecificRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_MunicipalProjectSpecificRiskMember" substitutionGroup="xbrli:item" />
  <element name="MunicipalProjectHousingRelatedRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_MunicipalProjectHousingRelatedRiskMember" substitutionGroup="xbrli:item" />
  <element name="MunicipalBondRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_MunicipalBondRiskMember" substitutionGroup="xbrli:item" />
  <element name="MortgageRelatedDerivativeInstrumentsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_MortgageRelatedDerivativeInstrumentsRiskMember" substitutionGroup="xbrli:item" />
  <element name="MortgageRelatedAndOtherAssetBackedSecuritiesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_MortgageRelatedAndOtherAssetBackedSecuritiesRiskMember" substitutionGroup="xbrli:item" />
  <element name="MarketRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_MarketRiskMember" substitutionGroup="xbrli:item" />
  <element name="MarketDisruptionsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_MarketDisruptionsRiskMember" substitutionGroup="xbrli:item" />
  <element name="MarketDiscountRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_MarketDiscountRiskMember" substitutionGroup="xbrli:item" />
  <element name="ManagementRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_ManagementRiskMember" substitutionGroup="xbrli:item" />
  <element name="LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" substitutionGroup="xbrli:item" />
  <element name="LoanOriginationRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_LoanOriginationRiskMember" substitutionGroup="xbrli:item" />
  <element name="LiquidityRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_LiquidityRiskMember" substitutionGroup="xbrli:item" />
  <element name="LeverageRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_LeverageRiskMember" substitutionGroup="xbrli:item" />
  <element name="IssuerRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_IssuerRiskMember" substitutionGroup="xbrli:item" />
  <element name="PreferredSharesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_PreferredSharesMember" substitutionGroup="xbrli:item" />
  <element name="CommonSharesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_CommonSharesMember" substitutionGroup="xbrli:item" />
  <element name="SeriesOneMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_SeriesOneMember" substitutionGroup="xbrli:item" />
  <element name="SeriesTwoMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170311_SeriesTwoMember" substitutionGroup="xbrli:item" />
</schema>
