B.Tech

So, you can get a lateral entry admission for engineering.

You can't do regular B.Tech parallel with your job. In such cases, the only option is to do AMIE. You get information on AMIE admission on this link:
http://www.amiestudycircle.com/amie-prospectus-admission.html.

Basically, government colleges are not so updated. So, their placement (campusing) & class quality not so good as like private colleges because there are lots of Politics. But, in maximum private colleges there fee is quite high/expensive. But, now, you get all those benefits under Singhania Univers

Eligibility Criteria for M.Tech in Environmental Studies:
A Maters degree in Environmental Science can be pursued if a candidate has a Bachelors in Engineering or technology in environmental or civil engineering. Since, you have a B.Tech degree you automatically qualify to apply for M.Tech in environ

M.Tech Environmental Science Eligibility
They should a pass degree of B.E./B.Tech. In CS/IT /Biotech/ Environmental Sciences or Master's degree in Programming/ Mathematics/Sciences.
* Hence, its not possible for an ECE graduate to opt for ME/M.Tech in environmental studies. There can be a possibility

Though it is entirely your choice. But, the best option for you is doing AMIE. It is the best option for working aspirants after passing Diploma:
Follow this link: http://www.amiestudycircle.com.

After B.Tech CSE, students have opportunities in the following government organisations :
BARC- Bhabha Atomic Research Centre. The Bhabha Atomic Research Centre (BARC) is India's premier nuclear research facility headquartered in Trombay, Mumbai, Maharashtra.
DRDO -The Defence Research and Developmen

Check out the reviews below for all required details:
https://www.shiksha.com/university/bharath-institute-of-higher-education-and-research-Chennai-24072/reviews.

No, for exams for B.Tech, only physics, chemistry and maths are compulsory subjects. For various engineering exams, check out the link below:
https://www.shiksha.com/articles/engineering-entrance-exams-in-india-blogId-5645.