Taxation of supply of goods or services barred where supply occurs outside a State or in import/export; Parliament defines principles. A State law cannot impose a tax on the supply of goods or of services or both when the supply takes place outside the State or in the course of import into or export out of India. Parliament may, by law, formulate principles to determine when a supply falls within those territorial categories, and prior explanatory and proviso formulations have been amended or omitted to reflect substitutional changes in terminology and scope.