Customs duty exemption on unwrought unalloyed lead reduces payable import duty under the specified tariff heading. The Central Government exempts unwrought unalloyed lead under the relevant tariff subheading from customs duty to the extent the duty exceeds a composite rate of 5% ad valorem plus a specified per tonne amount on importation, issued under sub section (1) of section 25 of the Customs Act, 1962 and superseding an earlier notification.