(1) When a notice of acquisition is served or is published under section 4, the land shall vest absolutely in the¹ [State] Government free from all encumbrances on the date the notice is so served or published in the official Gazette.
     (2) The competent authority may, at any time after the land has become so vested, proceed to take possession thereof:
     Provided that such authority shall not take possession of any building or part of a building under this sub-section without giving to the occupier thereof at least forty-eight hours' notice of his intention so to do, or such longer notice as may be reasonably sufficient to enable such occupier to remove his movable property from such building without unnecessary inconvenience.