Section 6(4) in The Indian Supply Service (Group `A') Rules, 2017
(4)The selection of officers for promotion to various grades of the Service shall be regulated in the following manner, namely.-(a)promotion to the Junior Time Scale of the Service shall be on the basis of `Selection';(b)promotion of officers from the posts in the Junior Time Scale to the posts in the Senior Time Scale (Ordinary Grade) of the Service shall be on the basis of `Selection';(c)grant of Non-Functional Second Grade in the Senior Time Scale of the Service shall be in the order of seniority based on the suitability taking into account the overall performance and experience in accordance with guidelines issued by the Central Government from time to time;(d)promotion of officers from the Senior Time Scale to the Junior Administrative Grade, from the Junior Administrative Grade to the Senior Administrative Grade and from the Senior Administrative Grade to the Higher Administrative Grade of the service, shall be on the basis of `Selection'.
