Ravina, Admissions to AIIMS will happen through All India Counselling. In 2019, the cut off for ST Category was 90.203. Now AIIMS had a different pattern than NEET. While AIIMS was conducted for 200 marks, NEET is conducted for 720 marks. So it is difficult to predict the exact scores that you might need. But to give you a vague idea, you will need atleast 650 and above. This is just a calculation based on the cut offs for 2019. For any guidance during counselling and admission, you can use our MBBS Companion: https://www.careers360.com/mbbs-companion