CSAB provides you the seats which have been left vacant during counseling via JOSAA. There is huge decline in cutoff of whichever branch have vacant seats. Generally no good branches have vacant seats from very good nits as well as pursuing b.Sc . in NITs

For general its closing rank is around 1 lac-1.2 lac .

For OBC their closing rank extend up to 1.6 lac.

For SC/ST Candidates their closing ranks are quite high up to 6 lac .

Good luck for your admissions