Refund of unutilised input tax credit: amended calculation formula and sectoral refund restriction apply prospectively to later applications. The circular clarifies that the amended refund calculation formula under sub rule (5) of Rule 89 applies prospectively and governs refund applications filed on or after its effective date, while earlier applications remain governed by the pre amendment formula. It also clarifies that the notification denying refunds for specified goods in chapters 15 and 27 where input tax exceeds output tax operates prospectively and applies only to refund applications filed on or after its effective date.