Section 21. For section 39 of the principal Act, the following section shall be substituted, namely:

21. For section 39 of the principal Act, the following section shall be substituted, namely:— "39. Save in respect of adolescents, the Central Government may make rules providing for the exemption to such extent, in such circumstances and subject to such conditions as may be specified, from the provisions of sections 28, 30, 31, 34 or subsection (5) of section 36— (a) of all or any of the persons employed in a mine, where an emergency involving serious risk to the safety of the mine or of the persons employed therein is apprehended; (b) of all or any of the persons so employed, in case of an accident, actual or apprehended; (c) of all or any of the persons engaged in work of a preparatory or complementary nature, which must necessarily be carried on for the purpose of avoiding serious interference with the ordinary working of the mine; (d) of all or any of the persons engaged in urgent repairs; and (e) of all or any of the persons employed in any work which for technical reasons must be carried on continuously." Amendment of section 40. Amendment of section 40.