Dear Tanmay 

The Post Graduate Program for Executives offered by IIM requires 

5 years professional full time job experience altleast

10+2+3 which is Bachelor degree from any recognized college 

And a valid Gmat score.

You have a good percentage in B.tech but average in class 12th and as you haven't provided any GMAT score I cant be fully sure but if you score above 90 percentile in gmat I am sure you can get IIM. I hope it helped