Hello Aswani..

Well 1st of all Congratulations for scoring such a good rank in the Cusat entrance examination for hydrochemistry qnd MSC in environmental Technology. 

Yes you can easily get a college for pursue your study in any stream what you want from both of the courses you mentioned. Now its on you that which course you want to pursue. Colleges are different for both in cusat entrance examination. 

Good luck and comment below if you have furthur queries regarding this...