Refund of unutilized ITC under inverted duty structure: eligibility limits, documentation requirements, and formula-based computation explained. Refunds of unutilized input tax credit due to an inverted duty structure are allowed under section 54(3) read with Rule 89 subject to exceptions where drawback is claimed or export duty applies. Claims must be filed electronically in FORM GST RFD-01, accompanied by invoice-level statements and supporting documents, and the electronic credit ledger is to be debited for the refund amount. Notifications and circulars modify eligible inputs, computation rules and sectoral restrictions.