Whenever it is necessary for a Corporation to carry out any of its works or to make any survey, examination or investigation, preliminary or incidental to the exercise of powers or the performance of duties by the Corporation under this Act, any ¹[officer or other employee] of the Corporation generally or specially empowered by the Corporation may, with the previous permission of the District Magistrate, enter upon any land or premises between sunrise and sunset, after giving reasonable notice of the intention to make such entry to the owner or occupier of such land or premises, and at any other time, with the consent in writing of the owner of occupier of such land or premises, for the purpose of the carrying out of such works or the making of such survey, examination or investigation.