Hi there,

For iits / nits there are basically these castes classification you can check which category you come under :-

1. General :- no caste reservation
2. General ews :- no caste reservation but reset based on annual income that must be less that 8lpa .
3. Sc :- Schedule caste, these are the schedule castes reservation if you belong to this cast category then you come under school
4. St:- schedule tribes :- generally it is takes to be the lowest reservation based on caste.
5. Obc :- other backwards caste these are the caste that are not general and also not sc/st.

I hope this helps.