I think u r talking about 'special duty'. .
It is levied u/s 3(1)(b) of the Central Excise Act, 1944. It is levied on the goods mentioned in the Second schedule to the Central Excise tariff Act, 1985.
So goods mentioned in the second schedule are liable to tax @ an additional rate of duty.
But currently, via notification no. 9/06-CE., dt. 1.3.2006, all the goods mentioned in the second schedule is exempted u/s 5A of the Central EXcise Act from the whole of the duty. Hence write now, no special duty is levied.
And that, goods are added/omitted from the schedule through notification...
For ur perusal, second schedule to CETA is attached here