Section 2(33)(d) in Assam General Sales Tax Act, 1993
(d)In any other case if the goods are in the State -(i)In the case of specific or ascertained goods, at the time the contract of sale or purchase is made; and(ii)In the case of unascertained or future goods, at the time of their appropriation to the contract of sale or purchase by the seller, whether the assent of the buyer to such appropriation is prior or subsequent to appropriation;