The cornerstone of this system is the mechanism of Input Tax Credit (ITC). Refund of Unutilised Credit: Further, Section 54(3), CGST Act in the context of refund of input tax credit states that a registered person may claim refund of any unutilised input tax credit, however no refund of unutilised input tax credit shall be allowed in cases other than—1. zero rated supplies made without payment of tax;2. where the credit has accumulated on account of rate of tax on inputs being higher than the rate of tax on output supplies (other than nil rated or fully exempt supplies). Refund of unutilised ITC u/s 54(3) is exhaustive and it expressly is confined to the following two situations:1. Whereas, no provision providing for lapse of input tax credit was incorporated in Section 29(5) . Accordingly, on the grounds discussed above, the taxpayer has a legitimate claim to seek refund of the unutilised ITC balance.