Notwithstanding anything contained in section 20, where the Central Government is satisfied that it is necessary in the public interest so to do, it may, by notification, exempt such of the goods which are re-imported after being exported for the purposes of repair, further processing or manufacture, as may be specified therein, from the whole or any part of duty of customs leviable thereon, subject to the following conditions, namely:-

(a) the goods shall be re-imported into India after such repair, further processing or manufacture, as the case may be, within a period of one year from the date on which the order permitting clearance for export is made;

(b) the exported goods are identifiable in the re-imported goods; and

(c) such other conditions as may be specified in that notification.