Is there any sales tax on imported product sold in local market while we donot pay sales tax in time of purchasing?

first the import tax is levied by ports authotitry which is governd by respective central govt in which there are various depts, but sales tax is levid by state govts which is revenue to repective state govts that is imposed on consumer which the vendor collects to pay back to revenue dept the vendor has to pay value added service vat to the central govt for him state tax wont be applicable.