If the Chairman or the Deputy Chairman is, by infirmity or otherwise, rendered incapable of carrying out his duties or is absent on leave or otherwise, in circumstances not involving the vacation of his appointment, or is sent on deputation outside India for any of the purposes of this Act, the Central Government may appoint another person to act in his place during his absence:
     Provided that the Chairman or the Deputy Chairman, while on deputation outside India may, if the Central Government by order so directs and subject to such conditions and restrictions as may be specified in that order, exercise such of the powers and perform such of the duties conferred or imposed on the Chairman or the Deputy Chairman, as the case may be, by or under this Act as he may deem necessary, and the Chairman or Deputy Chairman while exercising such powers and performing such duties shall be deemed to be a Trustee notwithstanding anything to the contrary contained in this Act.