Inventories (Details 1) ₨ in Millions, $ in Millions	12 Months Ended
Inventories (Details 1) ₨ in Millions, $ in Millions	Mar. 31, 2026 INR (₨)	Mar. 31, 2026 USD ($)	Mar. 31, 2025 INR (₨)	Mar. 31, 2024 INR (₨)
Classes of current inventories [abstract]
Raw materials, consumables and changes in finished goods and work in progress	₨ 114,875		₨ 94,580	₨ 78,526
Inventory write-downs	₨ 7,517	$ 80	₨ 5,220	₨ 3,563