Section 4(1)(b) in The Indian Forest Service (Initial Recruitment) Regulations, 1966
(b)(i)holds substantively a post in the State Forest Service;(ii)who has completed not less than eight years of continuous service (whether officiating or substantive) in that service, and(iii)who has completed not less than three years continuous service in an officiating capacity in a cadre post or in any other post declared equivalent thereto by the State Government concerned, shall be eligible for selection to the Service in the Senior scale.