IISER Entrance Exam

Minimum requirement in class 12 for OBC category is 60%

For SC it is around 55%.

But unfortunately you don't fall under these criteria so you are not eligible for IAT exam in OBC category.

But with the same percentile the SC students are eligible to take the IAT exam.

Admission to IAT (Indian Institute of Technology Joint Admission Test for M.Sc. or similar entrance exams for integrated programs) is primarily entrance-based. While your academic merit (12th-grade marks) is a foundational eligibility criterion, the selection for these highly competitive institutes is almost entirely determined by your performance in a rigorous national-level entrance examination. The scores from this specific entrance test are what ultimately decide your admission and rank, not just your board percentages alone.

IISER Berhampur cutoff 2025 for the BS + MS course across multiple specialisations stood at 3299 during the Round 1 cutoff for the students belonging to the General AI quota. So, considering the first-round cutoff rank, candidates must target to secure a rank up to 3299 and lower to improve their chances for admission. Please note that the required cutoff ranks vary for different rounds and categories. 

IISER Mohali cutoff 2025 has been released for different categories of students under the AI quota. For the General category, the cutoff rank for BS + MS admission across multiple specialisations was 1778. To view the category-wise ranks, refer to the table below:

it is usually in range of 3.5k but for iser pune it is in range of 1000 and this is the details of general category ranking 

Yes your St category certificate issued in January 2024 is likely still valid for the IAT 2025 exam while some exam may requires certificate issued after a specific dates such as April 1 2025 for JEE main the iat 2025 admission process does not specify such a date restriction for the certificate