Section 3(1)(a) in Central Excise Tariff Act, 1985
(a)in a case where the rate of duty as specified in [the First Schedule and the Second Schedule] [Substituted by s. 134 of the Finance Act, 1999 (27 of 1999).] as in force immediately before the issue of such notification is nil, a rate of duty not exceeding fifty per cent ad valorem expressed in any form or method;