Input tax credit restriction: suppliers of exempted or non GST supplies barred from claiming credit or refunds, proportionate for mixed supplies. Suppliers of exempted, nil rated or non GST goods or services shall not be entitled to input tax credit or refund on inputs (including input services and capital goods) used for such supplies; for mixed supplies credit may be apportioned proportionately. Such disallowed amounts are to be treated as 'ineligible input tax credit' with invoice details reported in returns. The model law should specify the full scope of ineligible credits and provide for allocation of these credits to importing States under Place of Supply Rules, with a system based apportionment mechanism implemented through the return process.