"If any question arises with reference to this Act or any rule made thereunder whether any person is or is not a foreigner or is not a foreigner of a particular class or description, the onus of proving that such person is not a foreigner or is not a foreigner of such particular class or description, as the case may be, shall, notwithstanding anything contained in the Indian Evidence Act, 1872 (1 o" . . . . .