This is something that will vary according to the year of admission. For any category, students up to a certain rank are decided according to the seats they have and are given provisional admission letters. 

Thereafter if any student among them does not accept the offer and any seat is left vacant then only the next ranked candidate is offered the seat.

In previous years in the general category, students till the rank of 58 were offered the provisional admission letters and all others beyond the rank were in the consideration pool in case some students did not accept the offer.