hi,

see generally b.tech course is of 4 years duration. In some of the institute b.tech in electrical, mechanical course offers in part time mode. however there is no colleges available which offers b.tech in environment engineering in part time mode as per data available at our portal . once you complete your b.tech in full time mode, you may pursue m.tech in environment engineering is part time course.

you may check the environment engineering colleges list at below link:

https://engineering.careers360.com/colleges/list-of-be-btech-in-environmental-engineering-colleges-in-india