Section 5(2) in The Assam Economic and Statistical Service Rules, 1973
(2)Additional Director of Economics and Statistics-Category II: Appointment shall be made by promotion from the select list prepared for this purpose from amongst eligible officers of category III who have rendered not less than 5 years of service in category III or a total of not less than 21 years of service in the service on the first day of the year in which the promotion is made.
