Customs exemption for jigat limits applicable customs duty to a capped ad valorem rate under section 25(1). The Central Government, under section 25(1) of the Customs Act, 1962, exempts jigat (bark of Machilus makarantha) falling under sub heading 1211.90 from so much of the customs duty specified in the First Schedule as exceeds the amount calculated at the rate of 30% ad valorem, thereby capping the effective duty on that product by notification.