IIT/NIT's have their own and different eligibility criteria. Check their individual websites and admission brouchers.

IIT/NIT's have relaxed eligibilty requirements for PWD catergory candidates. Hence, you may be eligibile for most IIT/NIT to apply.

Therefore do apply for IIT (Coap) and NIT (CCMT) because cutoff's are low for PWD candidates.

Firstly to convert CGPA into percentage you must multiply your CGPA with 9.5. so your percentage comes down to 55.29%.  according to the eligibility criteria set by ccmt:

Candidate should have scored at least 6.5 CGPA out of 10 or 60% for OC/OC-EW/OB category and 6.0 CGPA or 55% for SC/ST/PwD category in the qualifying degree.

If your cgpa is considered you are not eligible but by percentage matter you are. So apply via giving your percentage.