(2) The Central Government may, by notification, apply with effect from such date as may be specified in the notification the provisions of sub- section (3) to local or other authorities within the territory of India or under the control of the Government of India and to corporations 1[ or societies] owned or controlled by Government, not being a local or other authority or corporation 1[ or society] controlled or owned by a State Government: Provided that if the Central Government considers it expedient so to do for the purpose of facilitating transition to the scheme as envisaged by this Act, different dates may be so specified under this sub- section in respect of different classes of, or different categories under any class of, local or other authorities or corporations 1[ or societies].