(1)Where the erection of any building or the execution of any work has been commenced, or is being carried on, or has been completed without, or contrary to, the approval referred to in section 427, or in contravention of any of the provisions of this Act or the rules or the regulations made thereunder, the Municipal Commissioner or the Executive Officer may, in addition to any other action that may be taken under this Act, make an order directing that such erection or work shall be demolished by the person at whose instance the erection or the work has been commenced or is being carried on or has been completed, within such period, not being less than five days and more than fifteen days from the date on which a copy of the order of demolition with a brief statement of the reasons therefor has been delivered to such person, as may be specified in the order :Provided that no order of demolition shall be made unless such person has been given, by means of a notice served in such manner as the Municipal Commissioner or the Executive Officer may think fit, an opportunity of showing cause why such order shall not be made:Provided further that where the erection of any building or the execution of any work has not been completed, the Municipal Commissioner or the Executive Officer may, by the same order or by a separate order, whether made at the time of the issue of the notice under the first proviso or at any other time, direct such person to stop the erection of such building or the execution of such work until the expiry of the period within which an appeal against the order of demolition, if made, may be preferred under sub-section (3).Explanation. - In this chapter, "the person at whose instance" shall mean the owner, or the occupier, or any other person who causes the erection of any building or the execution of any work, including alterations or additions, if any, to be done, or does it by himself.