The principle of unjust enrichment is applicable in all the cases of Refund. but it is not allowed in the following case such as:
1) Refund of tax paid on zero-rated supplies of goods or services.
2) Unutilized input tax credit for zero-rated supplies made without payment of tax or if the credit has been accumulated on account where the rate of tax on inputs is higher than the rate of tax on output supplies.
3) In the cases where a Refund of tax paid on supply is not provided. It may be wholly or partially. it may also be in the case where invoice has not been issued.
4) Refund of tax in pursuance of Section 77 of the CGST/SGST Act. That is tax wrongly collected and paid to Central or State Government.
5) If the interest paid has not been passed on to any other person, in such cases, the other class of persons may notify the Government may notify having borne the incidence of tax.