Section 16(3)(d) in Bihar Secretariat Service Rules, 2010
(d)The seniority of Assistants, who had joined within one year from the date of issue of allotment order / appointment order, shall be in order of their merit but seniority of Assistant, who instead of joining within one year had joined after one year from the date of issue of allotment order / appointment order, shall be on the basis of their date of joining in their joining year according to their merit.