Exemption from Customs Duty: limited to secret/strategic imports and certified charitable imports subject to strict eligibility and monitoring. Exemption under Section 25(2) is limited to secret/strategic imports and bona fide charitable imports. Strategic exemptions cover government security needs, defence and certain R&D imports, excluding routine operational supplies and spares; government security requests must be forwarded by a Joint Secretary. Charitable exemptions require a registered nonprofit institution with three years' service, donations from known foreign entities, certification by prescribed authorities, exclusion of general-purpose items, and undertakings against commercial use. Ad-hoc Exemption Orders are monitorable, perpetual in conditions and enforceable by duty realization or penal action upon breach.