Proof of consent, etc. Of Board or Managing Director, officers or employees of the Board

Whenever, under this Act or any rule or regulation made there under, the doing or the omission to do anything or the validity of anything depends upon the approval, sanction, consent, concurrence, declaration, opinion, or satisfaction of- (a) The Board or the Managing Director, or (b) any officer or servant of the Board, a written document signed in case ( a ) by the Managing Director, and in case (b) by the said officer or servant, conveying or setting forth such approval, sanction, consent, concurrence, declaration, opinion or satisfaction shall be sufficient evidence of such approval, sanction, consent, concurrence, declaration, opinion, or satisfaction.