GST rate change applies to heavy water and other nuclear fuels under a revised schedule, effective from the notified date. An amendment places GST @ 5% on heavy water and other nuclear fuels by including them in Schedule I, effective from 22-09-2025 pursuant to Notification No. 9/2025-Integrated Tax (Rate) dated 17-09-2025, altering the taxable treatment and rate application for supplies of these goods.