Hello Aspirant!
As per the basic eligibility criteria, for pursuing M.Sc. in Environmental Science, a candidate must have qualified graduation with atleast 50% aggregate marks from any science stream subject. So, in general if we consider this, then yes, being a Chemistry graduate, you can apply for the course, provided you have secured the required minimum % of marks.

But this criteria can have some variations depending on the institution.
So, you can comment below the name of the college/university in which you are interested, to know about the exact eligibility criteria.

Hope this answer will help you.

Yes, you are eligible for Msc in environmental science. Because,you must have passed out your class 12th in Science Stream.

Certainly there will be new Subjects for you in Environmental Section which you can fined new or fresh but that will be not tough. There will be subjects like:  ecology,biology,physics,chemistry,geology,atmospheric etc., they are not a rocket science, if you have science background you don’t need to worry.

All the best!!