Indian Institute of Technology, Delhi

For IIT BOMBAY you have to secure the top rank in the JEE ADVANCE exam.
From JEE MAINS you get the NIT's college not IIT'S.
I am sending you an authentic link from where you get all information of cutoffs for IIT BOMBAY.please check it out.
link-https://www.shiksha.com/university/iit-bombay-indian-institute-of-technology-mumbai-54212/cutoff

The eligibility criteria of M.Sc. Mathematics of IIT Delhi is a Bachelors degree with minimum 55% of marks for general and OBCs and must have studied maths at least two years/four semesters at graduation level.
The admission will be based on ranks/marks obtained in JAM entrance exam.
Therefore, you can be eligible if meeting the above criteria.

Your expected JEE Main AIR is about 22278. The last year closing rank in asked course at IIIT-D was 40562 for Delhi region candidates. While 6442 was for outside Delhi region candidates. So, you can get if belongs to Delhi region.