Effective customs duty rates prescribed to cap excess duties for specified tariff headings under import regulations. The Central Government, under section 25(1) of the Customs Act, 1962, exempts imports falling under specified chapters, headings and sub headings of the Customs Tariff Schedule from any customs duty in excess of amounts calculated at rates set out in the notification Table. Column (3) provides the effective rate where the standard rate is leviable and column (4) where the preferential rate is leviable; rates are ad valorem unless otherwise specified. The Table prescribes ad valorem ceilings, specific duties and alternative formulations for numerous tariff items.