Hi Amit! It depends on which AIIMS institute you're aiming for. The qualifying marks for the general category is 50%, i.e., 100/200 and the percentile cut off is 99.01. The  following are the cut-off ranks for each institution : 

AIIMS New Delhi - 37

AIIMS Jodhpur - 871

AIIMS Bhopal - 1022

AIIMS Rishikesh - 1045 

AIIMS Bhubaneshwar - 1078

AIIMS Raipur- 1099

AIIMS Patna - 2949

All the best! Please ask if any more queries.