Hi Aniket,

There are many top tier colleges other than the IIMs that offer very good education along with great placements.

Also, many of tier-1 colleges like FMS Delhi, NITIE Mumbai, MDI Gurgaon, JBIMS XLRI Jamshedpur and the list can go on and on... which are actually better than new or baby IIMs

However, if your aim is to get into only IIMs, the only exam is Common Admission Test commonly known as CAT.

Different IIMs have different criteria for admission and those aren't limited to cgpa in Bachelor's. However, an average of 8.5 cgpa (83-85%) is considered decent.

Hope this helps!!