As per Rule 96, the refund of IGST paid on export of goods is processed and disbursed by Customs. For processing such refund, GST System transmits invoice level data of Table 6A in GSTR 1 subject to following validations:
1. GSTR 3B is filed for corresponding period, with admitted tax liability of IGST under Table 3.1 (b)
2. Export invoices are submitted in GSTR1/Table 6A, and have correct Shipping Bill number, shipping bill date and port number
3. The admitted tax liability of IGST under Table 3.1 (b) of GSTR 3B, is equal to, or greater than, the IGST amount claimed to have been paid under Table 6A of GSTR 1 of corresponding period.