Customs duty exemption for imports under Advance Licence conditioned on DEEC coverage, bond, port rules and export obligation discharge. Customs duty exemption applies to materials imported under Quantity Based Advance Licences issued on or after 1 April 1995 when covered by a Quantity Based Duty Exemption Entitlement Certificate issued in the prescribed form; conditions include production of the licence and certificate at customs clearance, execution of a bond or security (unless export obligation discharged), specified port/depot clearance, utilisation of imports only for discharge of export obligation, transferability only with endorsement, and discharge of export obligation within certificate period or approved extension, with interest and duty consequences on default.