Section 17(3)(b) in The Reserve Bank of India Act, 1934
(b)the purchase sale and rediscount of bills of exchange (including treasury bills) drawn in or on any place in any country outside India which is a member of the International Monetary Fund and maturing,—(i)in the case of bills of exchange arising out of any bona fide transaction relating to the export of goods from India, within one hundred and eighty days, and(ii)in any other case, within ninety days,