Can I do M.Tech in environmental engineering after doing M.Sc in chemistry?

Yes, you can do. M.Tech. Environmental Engineering is a 2-year full-time postgraduate course, the minimum eligibility for which is B.E. /B.Tech. Or equivalent degree with a minimum score of 60%. The programme is of 4 semesters, with the final semester based on the candidates chosen stream of study

Yes, of course you can apply, because according to the eligibility conditions Master's degree holders in any branch of Science/ Mathematics/ Statistics/ Computer Applications or equivalent and those who are in the final or pre-final year of such programmes can also apply. Eligible for M.Tech course