7. If any person kills any animal in an unnecessarily cruel manner he shall be punished with fine which may extend to two hundred Taka, or with imprisonment for a term which may extend to six months, or with both: Provided that nothing in this section shall render it an offence to kill any animal in a manner required by the religion or religious rites and usages of any race, sect, tribe or class, or for any bona fide scientific purpose or for the preparation of any medicinal drug.