All appointments of the staff of the Institute, except that of the Director, shall be made with the prior approval of the Central Government and in accordance with the procedure laid down in the Statutes,--
         (a) by the Executive Council, if the appointment is made on the academic staff in the post of Assistant Professor or above or if the appointment is made on the non-academic staff in any cadre, the maximum of the pay-scale for which is the same or higher than that of an Assistant Professor; and
         (b) by the Director, in any other case