Section 6(2) in The Indian Administrative Service (Regulation of Seniority) Rules, 1987
(2)If a promotee officer or officer appointed by selection is transferred from one cadre to another in public interest, his year of allotment shall remain unchanged and he shall be ranked inter-se with promotee officers or officers appointed by selection, as the case may be, having the same year of allotment in the cadre to which he is transferred with reference to the date on the basis of which he was assigned the year of allotment under these rules.
