For admission in environmental science course (BSC environmental science) a candidate must have qualified a his or her class 12th with physics, chemistry and biology as a main subject.
For a candidate who have done his or her BE / Btech degree in environmental science or civil engineering
This is another opportunity to do Mtech in in environment management.
If you have done your BE or BTech degree in biology related course then you can do bachelors in environmental science.
Best of luck.