Hello,

NITs and IIITs are given the status of Institute of National Importance by MHRD and thus has greatly helped them to establish themselves as the finest institutes of higher education in India. Thus, naturally, the demand for these colleges are way more than any other engineering colleges. Students tend to take up any course in these institutions over other colleges. Thus the closing rank of the NITs and IIITs are very very low. Its seat gets filled before the closing rank crosses 10k in JoSAA Counselling. 

Though the Home State quota applicable in NIT can definitely help you if you belong to certain states like north-eastern states. For example, Mechanical in NIT Agartala closed in 31k for SC Home State, in the 2nd round of JoSAA only. Without Home State, SC ranks hardly cross 10k for any branch in an institute till the last round.

Hope it helps. Thank You