Notwithstanding anything contained in the Income-tax Act, 1961 (43 of 1961) or any other enactment for the time being in force relating to tax on income, profits or gains-

(a) the Bureau;

(b) the existing Energy Management Centre from the date of its constitution to the date of establishment of the Bureau, shall not be liable to pay any income-tax or any tax in respect of their income, profits or gains derived.