AHMEDABAD MFG. & CALICO PTG.CO. LTD.&ANR vs UOI .

The Supreme Court upheld the constitutional validity of the amendments to Rules 9 and 49 of the Central Excises and Salt Act, 1944, and Section 51 of the Finance Act, 1982, which were made with retrospective effect. The Court clarified that excise duty cannot be levied on the weight of sized yarn, as it does not change the nature of the commodity from yarn to fabric. Consequently, the show-cause notices issued to the petitioners were quashed to prevent multiplicity of proceedings, referencing the precedent set in J.K. Cotton Spinning and Weaving Mills Ltd. v. Union of India, [1988] 1 SCR 700.