Admission to ITTs are made on the basis of JEE Advanced score. And to be eligible for JEE Advanced, you should have atleast a JEE Mains percentile of 85 and above. Again this is different for different Categories. According to the previous trends available at our article, for a chance at a seat in IIT, if you belong to General Category, Minimum percentage of marks in each subject is 10. This mounts to a minimum percentage of aggregate marks at 35. For EWS and OBC-NCL, it is 9 and 31.5. For SC,ST Categories, the minimum percentage of marks in each subject is 5 and the minimum percentage of aggregate marks is 17.5.