For nearly a decade, India’s interstate transmission system (ISTS) charges waiver has quietly shaped renewable power economics. By lowering landed tariffs on interstate sales, it encouraged the adoption of corporate open access and gave developers the confidence to scale. That cushion is now disappearing. The full waiver for solar and onshore wind expired on June 30, 2025, and has been replaced with a phased taper that will run until June 30, 2028.