Nothing in this Act shall apply—

(a) to any trade union registered under the Indian Trade Unions Act, 1926 (16 of 1926); or

(b) to any provident fund to which the provisions of the Provident Funds Act, 1925 (19 of 1925),apply; or

(c) if the Central Government so orders in any case, and to such extent or subject to such conditions or modifications as may be specified in the order, to any insurance business carried on by the Central Government or a State Government or a Government company as defined in section 617 of the Companies Act, 1956 (1 of 1956); or

(d) if the Authority so orders in any case, and to such extent or subject to such conditions or modifications as may be specified in the order, to—