Reporting of inter state supplies to unregistered persons ensures correct IGST apportionment and attracts penalty for non compliance. Registered suppliers must report inter State supplies to unregistered persons, composition taxable persons and UIN holders in Table 3.2 of FORM GSTR 3B and report inter State supplies to unregistered persons in Table 7B of FORM GSTR 1. IGST apportionment to the State of supply relies on the information in Table 3.2; omission causes non apportionment and mismatches in apportioned integrated tax. Registered persons are instructed to report place of supply and details in both tables as mandated, with penal consequences for contravention, and trade notices are to be issued to publicize this instruction.