(1) If the Central Government is of the opinion that it is necessary or expedient so to do in the public interest, it may, by order published in the Official Gazette, exempt any person or class of persons, supplying or distributing any commodity or class of commodities, from the operation of an order made under section 3.
     (2) Every order made under sub-section (1) shall be laid, as soon as may be after it is made, before each House of Parliament, while it is in session, for a total period of thirty days which may be comprised in one session or in two or more successive sessions, and if, before the expiry of the session immediately following the session or the successive sessions aforesaid, both Houses agree in making any modification in the order or both Houses agree that the order should not be made, the order shall thereafter have effect only in such modified form or be of no effect, as the case may be; so, however, that any such modification or annulment shall be without prejudice to the validity of anything previously done under that order.