JUDGMENT :

G.R. SWAMINATHAN, J.

1. This writ appeal is directed against the order dated 16.04.2018 allowing W.P. (MD) No. 15733 of 2014 filed by the respondents herein.

2. The respondents are working as vocational instructors in government higher secondary schools. They were placed in pre-revised scale of pay of Rs. 1400-2600 and revised scale of pay of Rs. 5500-175-9000. According to them, this fixation was erroneous since vide G.O.Ms. No. 840 dated 31.07.1990, the time scale of pay for vocational instructors having B.Sc. (Agri) qualification was directed to be fixed as Rs. 2000-3500 (equivalent to Rs. 6500-11100). They represented to the government seeking pay scale parity. The request was rejected by the Director of School Education, Chennai vide proceedings in Na. Ka. No. 24069/VI/V3/2014, dated 21.08.2014. Challenging the same, they filed W.P. (MD) No. 17533 of 2014. They contended that the issue raised by them had already been answered in their favour in W.A. (MD) No. 1344 of 2013 dated 14.08.2014 (The State of Tamil Nadu represented by its Secretary, School Education Depart