I have a bachelors degree in computer science engineering. Is it possible for me to do masters in any environmental science courses??

Leena,
I can answer this from a professional/industry perspective, but not a school administrator perspective so for credit/transfer logistics differ to your school. 

Absolutely! A foundational degree in computer science eng is applicable in virtually fields. At this point, you can think of computer science as a horizontal discipline required in every industry, every company, every academic pursuit. Technology is systematically disrupting every field- environmental science included. Think of all the ways your technical skills could be applied to the environmental field: air dispersion modeling, climate change projections, machine learning in agriculture, automation in water treatment, chemical sensing and detection, renewable energy technology and on and on and on.

I would even urge you to consider leveraging the technical skills you already have to get a job in the environmental field now. You can always go back to school if you feel you need additional technical skills in environmental science, but you currently have the most marketable degree out there and shouldn't underestimate that. Just a thought...

Good luck!
Molly