Anti dumping absorption measures may permit modification of duty to counteract absorption, including retrospective application by notification. The amendments empower the Central Government to notify retrospective commencement dates for anti dumping duties and to modify duties where absorption of anti dumping duty is found, defined by decreases in export price not matched by production cost or alternative prices. Exemptions for export oriented and special economic zone units are confined to specified situations, and reimposition and temporary revocation durations are respectively capped 'up to five years' and one year at a time.