Nothing in this Act shall apply to-
(a) the carrying out of works for the maintenance, improvement or other alterations of any building, being works which affect only the interior of the building or which do not materially affect the external appearance of the building;
(b) the carrying out by any local authority or by any department of Government of any works for the purpose of inspecting, repairing or renewing any drains, sewers, mains, pipes, cables or other apparatus including the breaking open of any street or other land for that purpose:
(c) the operational construction, (including maintenance, development and new construction) by or on behalf of a department of the Central Government;
(d) the erection of a building, not being a dwelling house, if such building is required for the purposes subservient to agriculture;
(e) the excavations (including wells) made in the ordinary course of agricultural operations; and
(f) the construction of unmetalled road intended to give access to land solely for agricultural purposes.