(4) If the Central Government is of opinion that it is necessary so to do for maintaining or increasing the production and supply of an essential commodity, it may, by order, authorise any person (hereinafter referred to as an authorised controller) to exercise, with respect to the whole or any part of any such undertaking engaged in the production and supply of the commodity as may be specified in the order such functions of control as may be provided therein and so long as such order is in force with respect to any undertaking or part thereof,--
(a) the authorised controller shall exercise his functions in accordance with any instructions given to him by the
Central Government, so, however, that he shall not have any power to give any direction inconsistent with the provisions of any enactment or any instrument determining the functions of the persons in charge of the management of the undertaking, except in so far as may be specifically provided by the order; and
(b) the undertaking or part shall be carried on in accordance with any directions given by the authorised controller under the provisions of the order, and any person having any functions of management in relation to the undertaking or part shall comply with any such directions.