For the AIIMS entrance exam, an ST category student should get an aggregate of 40%. The merit cutoff percentile for this category is 93.65 as per 2018 reports.

If one or more applicants achieve the same score then the ranking will be based on who go the highest in biology, chemistry, physics and also based on age. The percentile achieved for biology is given first preferance in this situation followed by chemisrty,physics and then the applicant's age.

Thank you for your question. 

The percentile cutoff for AIIMS in 2018 was 93.650542.

Whereas in 2017 , the cutoff was 94.1220114

24151 was the corresponding ranking fir 2018 

Whereas for AIIMS delhi, the cutoff rank was 2090.

Good luck.