The Tribunal held that where the notice under section 148 and the order under section 148A(d) were issued after expiry of three years from the end of the relevant assessment year, approval was required from the authority prescribed under section 151(ii). Since the approval had been granted only by the Principal CIT under section 151(i), the reassessment proceedings were vitiated for want of valid sanction. The subsequent amendment made by the Finance Act, 2023, was held to be prospective and could not cure the defect. Consequently, the reassessment was non est in law, and the Principal CIT could not invoke section 263 to revise such an invalid reassessment order. The revision order was accordingly quashed. (AY.2018-19)