Customs duty exemption for inward and outward processing allows notification-based relief subject to identifiability and re-export/re-import conditions. Sections 25A and 25B permit the Central Government, by notification and in the public interest, to exempt specified goods from whole or part of customs duty where goods are imported for or re-imported after repair, further processing or manufacture, subject to re-export or re-import within the prescribed period, identifiability of the goods in the outbound/inbound consignments, and any other conditions specified in the notification, with section 25B operating notwithstanding section 20.