(3)If no such undertaking as is mentioned in sub-section (2), is given, or if in a case where any such undertaking has been given, any work of improvement to which the undertaking relates, is not carried out within the specified period, or the building is at any time used in contravention of the terms of the undertaking, the Chief Officer shall, forthwith make an order of demolition of the building requiring that the building shall be vacated within a period to be specified in the order not being less than thirty days from the date of the order, and that it shall be demolished within six weeks of the expiration of that period.
