Section 142(9)(a) in The Punjab Goods and Services Tax Act, 2017
(a)where any return, furnished under the existing law, is revised after the appointed day and if, pursuant to such revision, any amount is found to be recoverable or any amount of input tax credit is found to be inadmissible, the same shall, unless recovered under the existing law, be recovered as an arrear of tax under this Act and the amount so recovered shall not be admissible as input tax credit under this Act;