Input tax credit entitlement requires invoice, receipt, tax payment and timely return filing; nonpayment within specified period triggers reversal. Registered persons may claim input tax credit for supplies used in business only if they possess a tax invoice or prescribed document, have received the goods or services (including deemed receipt), the tax on the supply has been paid to the Government in cash or by utilization of admissible input tax credit, and they have furnished the statutory return. Credits for supplies received in instalments accrue on receipt of the last instalment. Credits corresponding to tax on depreciated capital goods are disallowed. Failure by the recipient to pay the supplier within a prescribed period mandates addition of the credit to output liability with interest, though credit may be restored on payment.