Hey
If we compare the two colleges then Delhi Technological University is ranked at 36th position and Vellore Institute of Technology, Vellore, is ranked at 15th position. These rankings are given by the government of India in NIRF ranking on the basis of various parameters like research, placement, infrastructure, teaching and many more.
But here we are not just comparing two colleges for the same branch. We are talking about two different branches.
It should be completely your decision which branch you want to go for. If you are interested in mechanical engineering then go for it otherwise for the other one. Go for the syllabus of both the branches, take some time and then decide as it is about your career, I cannot decide on your behalf.
Because even if you take the branches based on the rankings of the colleges then also if you are not interested in that branch it will not take you anywhere as in the end we are all working for placement and if we not able to put 100% efforts then even a good colleges is of no use.

Also you can use the college predictor to know about all the colleges that you can get with your rank for your desired branch.
https://engineering.careers360.com/jee-main-college-predictor?utm_source=qna&utm_medium=jee_cp

VIT Vellore

Admissions Courses & Fees Placements Reviews

Shortlist

Brochure

DTU Delhi

Admissions Courses & Fees Cutoff Placements Reviews

Shortlist

Brochure

JNEC Aurangabad

Admissions Courses & Fees Placements Reviews

Shortlist

Brochure