v3.26.1
Fair values - Summary of Carrying Amounts And Fair Value of the Financial Instruments (Detail)
₨ in Millions, $ in Millions
Mar. 31, 2026
INR (₨)
Mar. 31, 2026
USD ($)
Mar. 31, 2025
INR (₨)
Interest-bearing loans and borrowings - long term | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value ₨ 710,908 $ 7,578 ₨ 642,691
Fair value 682,928 7,278 631,249
Interest accrued | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value 5,046 54 5,405
Fair value 5,046 54 5,405
Capital creditors | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value 44,176 471 32,545
Fair value 44,176 471 32,545
Purchase consideration payable | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value 4 0 44
Fair value 4 0 44
Liability for operation and maintenance | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value 1,323 14 1,323
Fair value 1,323 14 1,323
Interest-bearing loans and borrowings - short term | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value 56,859 606 80,327
Fair value 56,859 606 80,327
Trade payables | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value 17,820 190 8,173
Fair value 17,820 190 8,173
Liability for put options with non-controlling interests      
Financial liabilities      
Carrying value 5,644   6,358
Liability for put options with non-controlling interests | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value 5,644 60 6,371
Fair value 5,644 60 6,371
Derivative instruments - share warrants | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value 14 0 190
Fair value 14 0 190
Liability for put options - others | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value 9,047 96  
Fair value 9,047 96  
Derivative instruments - hedge instruments | Financial liabilities measured at amortised cost      
Financial liabilities      
Carrying value 103 1 857
Fair value 103 1 857
Security deposits | Financial assets measured at amortised cost      
Financial assets      
Carrying value 1,007 11 754
Fair value 1,007 11 754
Bank deposits with remaining maturity for more than twelve months | Financial assets measured at amortised cost      
Financial assets      
Carrying value 3,792 40 2,433
Fair value 3,792 40 2,433
Trade receivables | Financial assets measured at amortised cost      
Financial assets      
Carrying value 24,094 257 24,268
Fair value 24,094 257 24,268
Cash and cash equivalents | Financial assets measured at amortised cost      
Financial assets      
Carrying value 22,845 243 40,419
Fair value 22,845 243 40,419
Bank balances other than cash and cash equivalents | Financial assets measured at amortised cost      
Financial assets      
Carrying value 46,706 498 40,099
Fair value 46,706 498 40,099
Advances recoverable | Financial assets measured at amortised cost      
Financial assets      
Carrying value 713 8 634
Fair value 713 8 634
Interest accrued on fixed deposits | Financial assets measured at amortised cost      
Financial assets      
Carrying value 1,059 11 900
Fair value 1,059 11 900
Interest accrued on loans to related parties | Financial assets measured at amortised cost      
Financial assets      
Carrying value     15
Fair value     15
Government grant receivable | Financial assets measured at amortised cost      
Financial assets      
Carrying value 679 7 288
Fair value 679 7 288
Deferred consideration receivable | Financial assets measured at amortised cost      
Financial assets      
Carrying value 351 4 385
Fair value 351 4 385
Loans to related parties | Financial assets measured at amortised cost      
Financial assets      
Carrying value     284
Fair value     284
Loans to other body corporates | Financial assets measured at amortised cost      
Financial assets      
Carrying value 250 3  
Fair value 250 3  
Interest accrued on loans to other body corporate | Financial assets measured at amortised cost      
Financial assets      
Carrying value 15 0  
Fair value 15 0  
Insurance claim receivable | Financial assets measured at amortised cost      
Financial assets      
Carrying value 1,051 11 448
Fair value 1,051 11 448
Interest accrued on receivables | Financial assets measured at amortised cost      
Financial assets      
Carrying value 1,013 11  
Fair value 1,013 11  
Other current financial assets | Financial assets measured at amortised cost      
Financial assets      
Carrying value 474 5 107
Fair value 474 5 107
Investments | Financial assets measured at fair value through profit or loss      
Financial assets      
Carrying value 8,685 93 1,342
Fair value 8,685 93 1,342
Derivative instruments - hedge instruments | Financial assets measured at amortised cost      
Financial assets      
Carrying value 15,575 166 7,398
Fair value ₨ 15,575 $ 166 ₨ 7,398