Proviso amendment expands clause applicability by inserting 'or clause (iii)', made effective from the specified commencement date. Amendment to the Income-tax Act modifies the proviso to clause (ia) of section 16 by inserting the words, brackets and figures 'or clause (iii)' after 'clause (ii)', and declares that this insertion shall be deemed to have been in effect from the first day of April, 2025.