Section 8(6)(iii) in The Indian Forest Service (Pay) Rules, 2016
(iii)the junior next below the officer (or, if that officer has been passed over for the reason of inefficiency or unsuitability or because he is on leave or serving outside the ordinary line or forgoes promotion on his own volition to that grade, the officer next junior to him not so passed over) should also have started drawing pay in that Level from that date and his appointment thereto not being fortuitous; and