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          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_CounterpartyRiskMember" xlink:to="lab_cik0001170299_CounterpartyRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_CreditsRiskMember" xlink:label="loc_cik0001170299_CreditsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_CreditsRiskMember" xml:lang="en-US">Credit Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170299_CreditsRiskMember" xlink:to="lab_cik0001170299_CreditsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_CyberSecurityRiskMember" xlink:label="loc_cik0001170299_CyberSecurityRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_CyberSecurityRiskMember" xlink:to="lab_cik0001170299_CyberSecurityRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_DerivativesRiskMember" xlink:label="loc_cik0001170299_DerivativesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_DerivativesRiskMember" xlink:to="lab_cik0001170299_DerivativesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_DistributionRateRiskMember" xlink:label="loc_cik0001170299_DistributionRateRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_DistributionRateRiskMember" xlink:to="lab_cik0001170299_DistributionRateRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_HighYieldSecuritiesRiskMember" xlink:label="loc_cik0001170299_HighYieldSecuritiesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_HighYieldSecuritiesRiskMember" xlink:to="lab_cik0001170299_HighYieldSecuritiesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_InflationDeflationRiskMember" xlink:label="loc_cik0001170299_InflationDeflationRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_InflationDeflationRiskMember" xlink:to="lab_cik0001170299_InflationDeflationRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_InsuranceRiskMember" xlink:label="loc_cik0001170299_InsuranceRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_InsuranceRiskMember" xlink:to="lab_cik0001170299_InsuranceRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_LeverageRiskMember" xlink:label="loc_cik0001170299_LeverageRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_LeverageRiskMember" xlink:to="lab_cik0001170299_LeverageRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_LiquidityRiskMember" xlink:label="loc_cik0001170299_LiquidityRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_LiquidityRiskMember" xlink:to="lab_cik0001170299_LiquidityRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_LoanOriginationRiskMember" xlink:label="loc_cik0001170299_LoanOriginationRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_LoanOriginationRiskMember" xlink:to="lab_cik0001170299_LoanOriginationRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" xlink:label="loc_cik0001170299_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" xml:lang="en-US">Loans and Other Indebtedness Loan 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_cik0001170299_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" xlink:to="lab_cik0001170299_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_ManagementRiskMember" xlink:label="loc_cik0001170299_ManagementRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_ManagementRiskMember" xlink:to="lab_cik0001170299_ManagementRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_MarketRiskMember" xlink:label="loc_cik0001170299_MarketRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_MarketRiskMember" xlink:to="lab_cik0001170299_MarketRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_MarketDiscountRiskMember" xlink:label="loc_cik0001170299_MarketDiscountRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_MarketDiscountRiskMember" xlink:to="lab_cik0001170299_MarketDiscountRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_MarketDisruptionsRiskMember" xlink:label="loc_cik0001170299_MarketDisruptionsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_MarketDisruptionsRiskMember" xlink:to="lab_cik0001170299_MarketDisruptionsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_MortgageRelatedAndOtherAssetBackedInstrumentsRiskMember" xlink:label="loc_cik0001170299_MortgageRelatedAndOtherAssetBackedInstrumentsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_MortgageRelatedAndOtherAssetBackedInstrumentsRiskMember" 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_cik0001170299_MortgageRelatedAndOtherAssetBackedInstrumentsRiskMember" xlink:to="lab_cik0001170299_MortgageRelatedAndOtherAssetBackedInstrumentsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_MunicipalBondRiskMember" xlink:label="loc_cik0001170299_MunicipalBondRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_MunicipalBondRiskMember" xlink:to="lab_cik0001170299_MunicipalBondRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_MunicipalProjectSpecificRiskMember" xlink:label="loc_cik0001170299_MunicipalProjectSpecificRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_MunicipalProjectSpecificRiskMember" xlink:to="lab_cik0001170299_MunicipalProjectSpecificRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_OperationalRiskMember" xlink:label="loc_cik0001170299_OperationalRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_OperationalRiskMember" xlink:to="lab_cik0001170299_OperationalRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_OtherInvestmentCompaniesRiskMember" xlink:label="loc_cik0001170299_OtherInvestmentCompaniesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_OtherInvestmentCompaniesRiskMember" xlink:to="lab_cik0001170299_OtherInvestmentCompaniesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_PortfolioTurnoverRiskMember" xlink:label="loc_cik0001170299_PortfolioTurnoverRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_PortfolioTurnoverRiskMember" xlink:to="lab_cik0001170299_PortfolioTurnoverRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_PotentialConflictsOfInterestRiskAllocationOfInvestmentOpportunitiesMember" xlink:label="loc_cik0001170299_PotentialConflictsOfInterestRiskAllocationOfInvestmentOpportunitiesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_PotentialConflictsOfInterestRiskAllocationOfInvestmentOpportunitiesMember" xml:lang="en-US">Potential Conflicts of Interest Risk 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_cik0001170299_PotentialConflictsOfInterestRiskAllocationOfInvestmentOpportunitiesMember" xlink:to="lab_cik0001170299_PotentialConflictsOfInterestRiskAllocationOfInvestmentOpportunitiesMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_PrivacyAndDataSecurityRiskMember" xlink:label="loc_cik0001170299_PrivacyAndDataSecurityRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_PrivacyAndDataSecurityRiskMember" xlink:to="lab_cik0001170299_PrivacyAndDataSecurityRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_PrivatePlacementAndRestrictedSecuritiesRiskMember" xlink:label="loc_cik0001170299_PrivatePlacementAndRestrictedSecuritiesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_PrivatePlacementAndRestrictedSecuritiesRiskMember" xlink:to="lab_cik0001170299_PrivatePlacementAndRestrictedSecuritiesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_PuertoRicoSpecificRiskMember" xlink:label="loc_cik0001170299_PuertoRicoSpecificRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_PuertoRicoSpecificRiskMember" xlink:to="lab_cik0001170299_PuertoRicoSpecificRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_RegulatoryChangesRiskMember" xlink:label="loc_cik0001170299_RegulatoryChangesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_RegulatoryChangesRiskMember" xlink:to="lab_cik0001170299_RegulatoryChangesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_RegulatoryRiskCommodityPoolOperatorMember" xlink:label="loc_cik0001170299_RegulatoryRiskCommodityPoolOperatorMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_RegulatoryRiskCommodityPoolOperatorMember" xml:lang="en-US">Regulatory Risk Commodity Pool Operator [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170299_RegulatoryRiskCommodityPoolOperatorMember" xlink:to="lab_cik0001170299_RegulatoryRiskCommodityPoolOperatorMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_ReinvestmentRiskMember" xlink:label="loc_cik0001170299_ReinvestmentRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_ReinvestmentRiskMember" xlink:to="lab_cik0001170299_ReinvestmentRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_RepurchaseAgreementsRiskMember" xlink:label="loc_cik0001170299_RepurchaseAgreementsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_RepurchaseAgreementsRiskMember" xlink:to="lab_cik0001170299_RepurchaseAgreementsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_SecuritiesLendingRiskMember" xlink:label="loc_cik0001170299_SecuritiesLendingRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_SecuritiesLendingRiskMember" xlink:to="lab_cik0001170299_SecuritiesLendingRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_ShortExposureRiskMember" xlink:label="loc_cik0001170299_ShortExposureRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_ShortExposureRiskMember" xlink:to="lab_cik0001170299_ShortExposureRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_StructuredInvestmentsRiskMember" xlink:label="loc_cik0001170299_StructuredInvestmentsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_StructuredInvestmentsRiskMember" xlink:to="lab_cik0001170299_StructuredInvestmentsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_TaxRiskMember" xlink:label="loc_cik0001170299_TaxRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_TaxRiskMember" xlink:to="lab_cik0001170299_TaxRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_UsGovernmentSecuritiesRiskMember" xlink:label="loc_cik0001170299_UsGovernmentSecuritiesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_UsGovernmentSecuritiesRiskMember" xlink:to="lab_cik0001170299_UsGovernmentSecuritiesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_ValuationRiskMember" xlink:label="loc_cik0001170299_ValuationRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_ValuationRiskMember" xlink:to="lab_cik0001170299_ValuationRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_CreditDefaultSwapsRiskMember" xlink:label="loc_cik0001170299_CreditDefaultSwapsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_CreditDefaultSwapsRiskMember" xlink:to="lab_cik0001170299_CreditDefaultSwapsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_FocusedInvestmentRiskMember" xlink:label="loc_cik0001170299_FocusedInvestmentRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_FocusedInvestmentRiskMember" xlink:to="lab_cik0001170299_FocusedInvestmentRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_InsuranceLinkedAndOtherInstrumentsRiskMember" xlink:label="loc_cik0001170299_InsuranceLinkedAndOtherInstrumentsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_InsuranceLinkedAndOtherInstrumentsRiskMember" xlink:to="lab_cik0001170299_InsuranceLinkedAndOtherInstrumentsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_MortgageRelatedDerivativeInstrumentsRiskMember" xlink:label="loc_cik0001170299_MortgageRelatedDerivativeInstrumentsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_MortgageRelatedDerivativeInstrumentsRiskMember" xlink:to="lab_cik0001170299_MortgageRelatedDerivativeInstrumentsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_ZeroCouponBondStepUpsAndPaymentInKindSecuritiesRiskMember" xlink:label="loc_cik0001170299_ZeroCouponBondStepUpsAndPaymentInKindSecuritiesRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_ZeroCouponBondStepUpsAndPaymentInKindSecuritiesRiskMember" xlink:to="lab_cik0001170299_ZeroCouponBondStepUpsAndPaymentInKindSecuritiesRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_IssuerRiskMember" xlink:label="loc_cik0001170299_IssuerRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_IssuerRiskMember" xlink:to="lab_cik0001170299_IssuerRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_AMTBondsRiskMember" xlink:label="loc_cik0001170299_AMTBondsRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_AMTBondsRiskMember" xml:lang="en-US">AMT Bonds Risk [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170299_AMTBondsRiskMember" xlink:to="lab_cik0001170299_AMTBondsRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_MunicipalProjectHousingRelatedRiskMember" xlink:label="loc_cik0001170299_MunicipalProjectHousingRelatedRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_MunicipalProjectHousingRelatedRiskMember" xlink:to="lab_cik0001170299_MunicipalProjectHousingRelatedRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_NewYorkStateSpecificRiskMember" xlink:label="loc_cik0001170299_NewYorkStateSpecificRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_NewYorkStateSpecificRiskMember" xlink:to="lab_cik0001170299_NewYorkStateSpecificRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_IllinoisStateSpecificRiskMember" xlink:label="loc_cik0001170299_IllinoisStateSpecificRiskMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_IllinoisStateSpecificRiskMember" xlink:to="lab_cik0001170299_IllinoisStateSpecificRiskMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_AntiTakeoverProvisionsMember" xlink:label="loc_cik0001170299_AntiTakeoverProvisionsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_AntiTakeoverProvisionsMember" xml:lang="en-US">Anti Takeover Provisions [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170299_AntiTakeoverProvisionsMember" xlink:to="lab_cik0001170299_AntiTakeoverProvisionsMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_CertainAffiliationsMember" xlink:label="loc_cik0001170299_CertainAffiliationsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_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_cik0001170299_CertainAffiliationsMember" xlink:to="lab_cik0001170299_CertainAffiliationsMember" />
          <link:loc xlink:type="locator" xlink:href="cik0001170299-20251231.xsd#cik0001170299_AdditionalRisksAssociatedWithTheFundsPreferredSharesMember" xlink:label="loc_cik0001170299_AdditionalRisksAssociatedWithTheFundsPreferredSharesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_cik0001170299_AdditionalRisksAssociatedWithTheFundsPreferredSharesMember" xml:lang="en-US">Additional Risks Associated With The Funds Preferred Shares [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cik0001170299_AdditionalRisksAssociatedWithTheFundsPreferredSharesMember" xlink:to="lab_cik0001170299_AdditionalRisksAssociatedWithTheFundsPreferredSharesMember" />
        </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="ARPSMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_ARPSMember" substitutionGroup="xbrli:item" />
  <element name="RVMTPMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_RVMTPMember" substitutionGroup="xbrli:item" />
  <element name="AssetAllocationRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_AssetAllocationRiskMember" substitutionGroup="xbrli:item" />
  <element name="CaliforniaStateSpecificRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_CaliforniaStateSpecificRiskMember" substitutionGroup="xbrli:item" />
  <element name="CallRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_CallRiskMember" substitutionGroup="xbrli:item" />
  <element name="ConfidentialInformationAccessRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_ConfidentialInformationAccessRiskMember" substitutionGroup="xbrli:item" />
  <element name="CounterpartyRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_CounterpartyRiskMember" substitutionGroup="xbrli:item" />
  <element name="CreditsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_CreditsRiskMember" substitutionGroup="xbrli:item" />
  <element name="CyberSecurityRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_CyberSecurityRiskMember" substitutionGroup="xbrli:item" />
  <element name="DerivativesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_DerivativesRiskMember" substitutionGroup="xbrli:item" />
  <element name="DistributionRateRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_DistributionRateRiskMember" substitutionGroup="xbrli:item" />
  <element name="HighYieldSecuritiesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_HighYieldSecuritiesRiskMember" substitutionGroup="xbrli:item" />
  <element name="InflationDeflationRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_InflationDeflationRiskMember" substitutionGroup="xbrli:item" />
  <element name="InsuranceRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_InsuranceRiskMember" substitutionGroup="xbrli:item" />
  <element name="LeverageRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_LeverageRiskMember" substitutionGroup="xbrli:item" />
  <element name="LiquidityRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_LiquidityRiskMember" substitutionGroup="xbrli:item" />
  <element name="LoanOriginationRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_LoanOriginationRiskMember" substitutionGroup="xbrli:item" />
  <element name="LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_LoansAndOtherIndebtednessLoanParticipationsAndAssignmentsRiskMember" substitutionGroup="xbrli:item" />
  <element name="ManagementRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_ManagementRiskMember" substitutionGroup="xbrli:item" />
  <element name="MarketRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_MarketRiskMember" substitutionGroup="xbrli:item" />
  <element name="MarketDiscountRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_MarketDiscountRiskMember" substitutionGroup="xbrli:item" />
  <element name="MarketDisruptionsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_MarketDisruptionsRiskMember" substitutionGroup="xbrli:item" />
  <element name="MortgageRelatedAndOtherAssetBackedInstrumentsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_MortgageRelatedAndOtherAssetBackedInstrumentsRiskMember" substitutionGroup="xbrli:item" />
  <element name="MunicipalBondRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_MunicipalBondRiskMember" substitutionGroup="xbrli:item" />
  <element name="MunicipalProjectSpecificRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_MunicipalProjectSpecificRiskMember" substitutionGroup="xbrli:item" />
  <element name="OperationalRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_OperationalRiskMember" substitutionGroup="xbrli:item" />
  <element name="OtherInvestmentCompaniesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_OtherInvestmentCompaniesRiskMember" substitutionGroup="xbrli:item" />
  <element name="PortfolioTurnoverRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_PortfolioTurnoverRiskMember" substitutionGroup="xbrli:item" />
  <element name="PotentialConflictsOfInterestRiskAllocationOfInvestmentOpportunitiesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_PotentialConflictsOfInterestRiskAllocationOfInvestmentOpportunitiesMember" substitutionGroup="xbrli:item" />
  <element name="PrivacyAndDataSecurityRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_PrivacyAndDataSecurityRiskMember" substitutionGroup="xbrli:item" />
  <element name="PrivatePlacementAndRestrictedSecuritiesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_PrivatePlacementAndRestrictedSecuritiesRiskMember" substitutionGroup="xbrli:item" />
  <element name="PuertoRicoSpecificRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_PuertoRicoSpecificRiskMember" substitutionGroup="xbrli:item" />
  <element name="RegulatoryChangesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_RegulatoryChangesRiskMember" substitutionGroup="xbrli:item" />
  <element name="RegulatoryRiskCommodityPoolOperatorMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_RegulatoryRiskCommodityPoolOperatorMember" substitutionGroup="xbrli:item" />
  <element name="ReinvestmentRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_ReinvestmentRiskMember" substitutionGroup="xbrli:item" />
  <element name="RepurchaseAgreementsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_RepurchaseAgreementsRiskMember" substitutionGroup="xbrli:item" />
  <element name="SecuritiesLendingRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_SecuritiesLendingRiskMember" substitutionGroup="xbrli:item" />
  <element name="ShortExposureRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_ShortExposureRiskMember" substitutionGroup="xbrli:item" />
  <element name="StructuredInvestmentsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_StructuredInvestmentsRiskMember" substitutionGroup="xbrli:item" />
  <element name="TaxRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_TaxRiskMember" substitutionGroup="xbrli:item" />
  <element name="UsGovernmentSecuritiesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_UsGovernmentSecuritiesRiskMember" substitutionGroup="xbrli:item" />
  <element name="ValuationRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_ValuationRiskMember" substitutionGroup="xbrli:item" />
  <element name="CreditDefaultSwapsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_CreditDefaultSwapsRiskMember" substitutionGroup="xbrli:item" />
  <element name="FocusedInvestmentRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_FocusedInvestmentRiskMember" substitutionGroup="xbrli:item" />
  <element name="InsuranceLinkedAndOtherInstrumentsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_InsuranceLinkedAndOtherInstrumentsRiskMember" substitutionGroup="xbrli:item" />
  <element name="IssuerRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_IssuerRiskMember" substitutionGroup="xbrli:item" />
  <element name="MortgageRelatedDerivativeInstrumentsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_MortgageRelatedDerivativeInstrumentsRiskMember" substitutionGroup="xbrli:item" />
  <element name="ZeroCouponBondStepUpsAndPaymentInKindSecuritiesRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_ZeroCouponBondStepUpsAndPaymentInKindSecuritiesRiskMember" substitutionGroup="xbrli:item" />
  <element name="AMTBondsRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_AMTBondsRiskMember" substitutionGroup="xbrli:item" />
  <element name="MunicipalProjectHousingRelatedRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_MunicipalProjectHousingRelatedRiskMember" substitutionGroup="xbrli:item" />
  <element name="NewYorkStateSpecificRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_NewYorkStateSpecificRiskMember" substitutionGroup="xbrli:item" />
  <element name="IllinoisStateSpecificRiskMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_IllinoisStateSpecificRiskMember" substitutionGroup="xbrli:item" />
  <element name="AntiTakeoverProvisionsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_AntiTakeoverProvisionsMember" substitutionGroup="xbrli:item" />
  <element name="CertainAffiliationsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_CertainAffiliationsMember" substitutionGroup="xbrli:item" />
  <element name="AdditionalRisksAssociatedWithTheFundsPreferredSharesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_AdditionalRisksAssociatedWithTheFundsPreferredSharesMember" substitutionGroup="xbrli:item" />
  <element name="CommonSharesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="cik0001170299_CommonSharesMember" substitutionGroup="xbrli:item" />
</schema>
