There is no percentage barrier to be eligible for Jee Main. The basic eligibility critdtia is that the candidate must have passed 10+2 with Physics, Mathematics as compulsory subjects [along with one of Chemistry/Biotechnology/Biology/Technical/Vocational] from a recognized board. For admission to IITs, NITs, IIITs, CFTIs, a general and OBC candidate need to have at least 75% marks in the qualifying examination or be in top 20 percentile of the respective board. And it is 65% for students belonging to SC, ST or Pwd categories. For B.Arch, candidates should have passed 10+2 or equivalent exam with minimum 50% aggregate marks from a recognized board. For B.arch, candidates should have passed in Physics, Chemistry and Mathematics and Only compulsory subject for B.Plan is Mathematics. Now Jee Main 2022 is so far that we can't predict it. The exam conducting authority may change the eligibility criteria depending on the situation then, like they did this year.
http://engineering.careers360.com/articles/jee-main-eligibility-criteria/amp