Excise duty exemption on alloy steel wire plated with base metals reduces taxable duty to a capped per tonne rate. The Central Government exempts wire of alloy steel plated or coated with base metals, classified under the relevant tariff sub heading, from so much of the basic excise duty specified in the tariff schedule as is in excess of a specified per tonne cap, thereby fixing the effective taxable rate at that cap for the described product.