GATE Scores

I think there is a mistake in your question.
Because GATE is meant for Post-Graduation courses but it can't make you to get into B.Tech
First of all, you have to complete your B.Tech to be eligible for the GATE.
But, if you want to join in B.Tech CSE in GITAM, you have to appear for GAT entrance exam conducted by GITAM University and the cut-off will be changing every year based on the number of applicants and GAT score around 300+ out of 400 can easily assure your admission into CSE even in Vizag campus.
Even if you are not able to score the cut-off don't be disappointed because later, if you contact to take admissions desk of GITAM, you can get a seat if the seats were still vacant.
All the best.

Colleges providing M.Tech in Environmental Science without GATE score:
1. Indian Institute of Technology, Delhi
2. Indira Gandhi Open University, Delhi
3. Rajiv Gandhi Proudyogiki Vishwavidyalaya
4. Indian Institute of Technology, Kharagpur
5. Thapar Institute of Engineering and Technology, Patiala.
6. Jamia Millia Islamia, New Delhi
7. Visveswariah Technological University, AIT, Chikmagalur
8. Indian Institute of Technology, Madras
9. Indian Institute of Technology, Delhi
10. Indian Institute of Technology, Kanpur
11. Indian Institute of Technology, Madras
12. Jamia Millia Islamia, New Delhi
13. Visveswariah Technological University, AIT, Chikmagalur
14. Amity University
15. Visveswariah Technological University
Regards.