138. (1)(a) The Board or any other income-tax authority specified by it by a general or special order in this behalf may furnish or cause to be furnished to—
(i) any officer, authority or body performing any functions under any law relating to the imposition of any tax, duty or cess, or to dealings in foreign exchange as defined in clause (n) of section 2 of the Foreign Exchange Management Act, 1999 (42 of 1999); or
(ii) such officer, authority or body performing functions under any other law as the Central Government may, if in its opinion it is necessary so to do in the public interest, specify by notification in the Official Gazette in this behalf,
any such information received or obtained by any income-tax authority in the performance of his functions under this Act, as may, in the opinion of the Board or other income-tax authority, be necessary for the purpose of enabling the officer, authority or body to perform his or its functions under that law.
(b) Where a person makes an application to the Principal Chief Commissioner or Chief Commissioner or Principal Commissioner or Commissioner in the prescribed form35 for any information relating to any assessee received or obtained by any income-tax authority in the performance of his functions under this Act, the Principal Chief Commissioner or Chief Commissioner or Principal Commissioner or Commissioner may, if he is satisfied that it is in the public interest so to do, furnish or cause to be furnished the information asked for and his decision in this behalf shall be final and shall not be called in question in any court of law.
(2) Notwithstanding anything contained in sub-section (1) or any other law for the time being in force, the Central Government may, having regard to the practices and usages customary or any other relevant factors, by order notified in the Official Gazette, direct that no information or document shall be furnished or produced by a public servant in respect of such matters relating to such class of assessees or except to such authorities as may be specified in the order.