Section 47(1)(b) in Road Transport Corporations Act, 1950
(b)no suit, prosecution or other legal proceeding shall lie against the Government of Bombay or any member of the Board or Any officer or servant of the existing Corporation in respect of any action taken by, or in relation to the setting up of, the existing Corporation or Board merely on the ground of any defect in, or invalidity of, the enactment or order under which the existing Corporation or Board was constituted.