Hello Dheeraja,

Yes, you can do M Tech in Environmental management.

Current status of M tech in Environmental engineering  is

Most of Post graduation as of M tech, institutes are not well adequate about teaching and providing thorough knowledge about the branch.

This branch awareness has grown but Institutes only suck money but never give you exposure to industry and placements.

Suppose you complete Mtech but getting jobs is highly difficult because of no field knowledge and for design, you don't have experience.

Anyhow if you get jobs what shall be salary .it's less than b tech fresher gets  ..around 10k-15k.

I prefer you do Post graduation in Environmental engineering either from IIT or Abroad (MS)

The only advantage of doing M tech is you can go for teaching line and pursue PhD and PhD will depend upon guide selection and research arena.

These all above are facts and if you want to know exactly .. Visit all alumnus and ask their opinion.