suggesting that the past provisions would continue to apply even after the substitution for the assessment periods prior to substitution. In fact there are strong indications to the contrary. We may recall, that time limits for issuing notice under Section 148 of the Act have been modified under substituted Section 149. Clause (a) of sub-section (1) of Section 149 reduces such period to three years instead of originally prevailing four years under normal circumstances. Clause (b) extends the upper limit of six years previously prevailing to ten years in cases where income chargeable to tax which has escaped assessment amounts to or is likely to amount to 50 lacs or more. Sub-section (1) of Section 149 thus contracts as well as expands the time limit for issuing notice under Section 148 depending on the question whether the case falls under clause (a) or clause (b). In this context the first proviso to Section 149(1) provides that no notice under Section 148 shall be issued at any time in a case for the relevant assessment year beginning on or before 01.04.2021 if such notice could not have been issued at that time on account of being beyond the time limit specified under the provisions of clause (b) of subsection (1) of Section 149 as they stood immediately before the commencement of the Finance Act, 2021. As per this proviso thus no notice under Section 148 would be issued for the past assessment years by resorting to the larger period of limitation prescribed in newly substituted clause (b) of Section 149(1). This would indicate that the notice that would be issued after 01.04.2021 would be in terms of the substituted Section 149(1) but without breaching the upper time limit provided in the original Section 149(1) which stood substituted. This aspect has also been highlighted in the memorandum explaining the proposed provisions in the Finance Bill. If according to the revenue for past period provisions of section 149 before amendment were applicable, this first proviso to section 149(1) was wholly unnecessary. Looked from both angles, namely, no indication of surviving the past provisions after the substitution and in fact an active indication to the contrary, inescapable conclusion that we must arrive at is that for any action of issuance of notice under Section 148 after 01.04.2021 the newly introduced provisions under the Finance Act, 2021 would apply. Mere extension of time limits for issuing notice under section 148 would not change this position that obtains in law. Under no circumstances the extended period available in clause (b) of sub-section (1) of Section 149 which we may recall now stands at 10 years instead of 6 years previously available with the revenue, can be pressed in service for reopening assessments for the past period. This flows from the plain meaning of the