Hi aspirant ,

Yes , you can come under top 20 percentile but chances are less. But you can get admission in IIT with this much percentage if you qualify jee advance , but for this year only . For this year iit has given exemption from 75 percent criteria rule due to covid  - 19 . A student with any percentage ( passed student ) can get admission in iit this year if he/she qualify jee advance and achieves good rank in it . according to the rank the admission will be given jee advanced rank.

hope this help you

best of luck

stay safe stay happy