Hello Premal
IIMs put a great emphasise on the profile of the candidate and how well he/ she has performed in the academics.
If your profile is not that attractive, they will simply not give you a call saying that you have a poor profile.
Since the marks of graduation and CAT score matters the most, try your best to maintain good CGPA and a good score in CAT.
Except a few IIMs, you would get a call from most of them if your percentile is more than 99.
Hope it helped.