NIT

Hello Abhishek,
Yes, 12th marks have the same important as for IIT. You must score more than 75% in your 12th board exams to get admission even in NITs. Also, if not, you are not eligible for admission in NITs.
All the best.

Yes, 220 is sufficient to get admission in a good college. You should wait for the counselling.

You need to score a minimum of 140 marks.

No, you cannot as to to fulfil the eligibility criteria of JEE Mains, you need to score a minimum of 75% marks in class 12th.

Hi,
According to the cutoff you cannot get NIT, Warangal with this rank. Please see the cutoff for all NITs from this link:
http://jointseatallocationauthority.in/josaa-cut-marks-iits-nits-scstobcgeneral/

NIA being a premier institute in the field of insurance founded by Ministry of Finance GOI, LIC, Four GIC companies is a reputed institute in insurance industry. NIA established for the training and development of insurance professionals in the country. Placement from NIA is also in the related areas of insurance only. Where as the other institutes courses/programs are in general not in insurance and the placement in the insurance field from other colleges mostly in other domain. NIA stands out from rest of the colleges. Thus, comparing with other colleges is not possible.
Sorry.

TIFR, DU, IISC, IIST, Raman Institute, Indian Institute of Astro physics, Indian Mathematics Institute are some known institutes you can look for apart from IITs and NITs.

Yes, you can get admission in NIT.

As per the closing rank given by Josaa you must secure the required marks so that your rank is in between 1-20k or maximum 30k, then only you can get into NITs.