Section 133(1) in The Central Goods and Services Tax Rules, 2017
(1)The Authority shall, within a period of [six] [Substituted 'three' by Notification No. G.S.R. 457(E), dated 28.6.2019.] months from the date of the receipt of the report from the [Director General of Anti-profiteering] [Substituted 'Director General of Safeguards' by Notification No. G.S.R. 611(E), dated 6.7.2018 (w.e.f. 19.6.2017).] determine whether a registered person has passed on the benefit of the reduction in the rate of tax on the supply of goods or services or the benefit of input tax credit to the recipient by way of commensurate reduction in prices.