Hello Shreyasi. According to JoSAA five subjects are taken into account while calculating top 20 percentile. These five subjects are- Physics, Chemistry, Mathematics, a language subject (subject with higher marks will be considered if you have studied more than one language subject), any other subject ( subject with highest marks will be considered). Or you can qualify for jee mains if you have scored 75% or more in your 12th boards.

For any further information please refer to the link below.

https://engineering.careers360.com/articles/top-20-percentile-cutoff-of-class-12-boards-for-iit-admission

Hope this helps. For any further queries feel free to comment down below.

All the best!