Excise exemption for PVC compounds where no input duty credit is availed, otherwise subject to an ad valorem duty. Amendment substitutes the tariff entry for PVC compounds to provide a conditional nil excise rate where no credit for duty on inputs has been availed under the input credit rules, and a thirty per cent ad valorem duty where that condition is not satisfied; enacted under rule 8(1) of the Central Excise Rules, 1944.