GSTIN not required for exclusively exempt importers/exporters; PAN/IEC must be quoted and consignments not delayed. Where importers or exporters deal exclusively in goods not taxable or wholly exempt under the CGST/IGST framework, GSTIN is not required and PAN authorised as IEC suffices; registration provisions under the CGST Act apply to IGST by statutory linkage. Customs will not hold up consignments where GSTIN is legally unnecessary, and importers, exporters and brokers must quote PAN in bills of entry and shipping bills for clearance, with implementation issues to be reported to the customs office.