Section 17(1)(f) in The Integrated Goods and Services Tax Act, 2017
(f)in respect of import of goods or services or both made in a financial year by a registered person, where he does not avail of the said credit within the specified period and thus remains in the integrated tax account after expiry of the due date for furnishing of annual return for such year in which the supply was received, the amount of tax calculated at the rate equivalent to the central tax on similar intra-State supply shall be apportioned to the Central Government.