IGST exemption for CSD and Unit Run Canteen supplies to authorised customers and between them under section 6(1). An exemption from integrated tax is provided for supplies by the CSD to Unit Run Canteens, supplies by the CSD to authorised customers, and supplies by Unit Run Canteens to authorised customers; the exemption is exercised under the Central Government's power in section 6(1) of the Integrated Goods and Services Tax Act, relieving such inward supplies from the whole of the integrated tax leviable under section 5, and tariff references are to be interpreted by the First Schedule to the Customs Tariff Act, 1975.