Hello dear aspirant

If you are a general or OBC student,  then you are not eligible for getting admission in IIT. Because to get into IIT ,  you need a minimum of 75% in your class 12th examination.
If you belong to sc Or st,  then you are eligible to get admission in IIT,  which again depends on your JEE advanced rank.
Hope I am clear

Hello Amit
As per the eligibility criteria of the percentage :
If you belong to general or OBC category than you are not eligible to take admission in IIT .
But if you belong to sc/st category than yes ofcourse you are eligible.
There is one way more i.e percentile if your marks is within the top 20 percentile of your boards than you can take admission.( For this you should see the cut off marks for top 20 percentile on josaa site.)
Good luck