Section 16(1)(i) in The Indian Foreign Service Branch 'B' Rules, 2017
(i)66.67 per cent of the regular vacancies in the Grade of Private Secretary shall be filled by promotion (seniority quota) on seniority basis from amongst Personal Assistants of the Stenographers' Cadre of the Service who have on the crucial date undergone and successfully completed such mandatory training programme(s) as may be prescribed by the Ministry of External Affairs and rendered not less than eight years approved service in that grade; and