Transitional protection for freely permitted trade: exports and imports allowed if shipment occurs within original validity. The chapter sets the Policy's operative duration and confirms the Central Government's power to amend it by notification. Pre-existing authorisations continue to be valid for their original purpose and duration unless specified otherwise. Exports or imports freely permitted before the imposition of restrictions are ordinarily permitted provided shipment occurs within original validity and available balance and is supported by an irrevocable commercial letter of credit established prior to the restriction; administrative time limits for operationalising such LCs may be prescribed.