NITs are the institutes of National Importance and also receive special recognition from the Govt. of India.
In 2002, all RECs( Regional Engineering Colleges) where upgraded to NITs by MHRD (Ministry of Human Resources and Development) instead of creating new IITs.
The central government controls NITs and provide fundings to them. However, thses are autonomous institutes which allows them to set up their own curriculum.
There are total 31 NITs in India and all are centrally funded from the Govt of India