IIST takes admission through JEE Advanced. First, you have to qualify for JEE Main exam in order to be eligible for JEE Advanced.

In order to be eligible for IIST you have to get minimum prescribed category-wise marks

1- General category- At least 20% marks in aggregate and at least 5% marks in each of three subjects.

2- Other Backward Community- Non Creamy Layer (OBC-NCL) candidate- At least 18% marks in aggregate and at least 4.5% marks in each of the three subjects.

3- SC/ST/PD Candidates- At least 10% marks in aggregate and at least 2.5% marks in each of three subjects.

Good Luck!!