13. Notwithstanding anything contained in this Part, the Government or the Authority may, by a special order passed in respect of any act or work specified in section 7, or by a general order in respect of any class of such acts or works, authorise the Engineer to pass, after such enquiry as is prescribed in section 9, an order that such act or work or any modification thereof may be done or executed without previous reference to any superior authority; or the Government or the Authority may authorise the Project Director of the Authority to pass such order without previous reference to any superior authority: Provided that every such order passed under the authorisation of the Government or the Authority, as the case may be, shall be subject to the provisions of section 67.