IIIT Delhi admits students into its B.Tech courses based on these ranks. IIIT Delhi ranks are released after taking into account both the JEE Main ranks and the bonus marks (awarded to eligible students).
Bonus marks are awarded for remarkable achievement in National Olympiads (NSEC, INMO, etc), KVPY, NTSE, FIDE ratings (chess), and much more.
The final rank list contains both kinds of students- those who got bonus marks, and those who did not. Admissions are finally done on the basis of this ranking list.