Customs tariff amendment: polytetrafluoroethylene added to the schedule with a specified ad valorem duty under section 25. Central Government, invoking section 25 of the Customs Act, 1962, amends Notification No. 88/87-Cus by renumbering the existing Sl. No.11 as Sl. No.12 and inserting a new Sl. No.11 in the Table specifying Polytetrafluoroethylene with an ad valorem duty rate, thereby modifying the Customs Tariff schedule under the earlier notification.