21. (1) Subject to the provisions of sub section (2), a foreign fishing vessel may enter the Bangladesh fisheries waters without a licence for the purpose of- (a) passage through such waters in the course of a voyage to destination outside such waters; (b) averting imminent danger where the vessel is in distress, to the safety of the vessel or of its crew; or (c) rendering assistance to persons, ships or aircraft in danger or distress; or (d) obtaining emergency medical assistance for a member of the crew; or (e) for any other purpose recognised by international law. (2) Any foreign fishing vessel entering the Bangladesh fisheries waters for any purpose set out in sub section (1) shall- (a) observe such rules as may be prescribed; and (b) return outside such waters as soon as the purpose for which it entered has been fulfilled.