Hello!

Eligibility criteria for admission in IISER is as follows:

• Candidates belonging to GEN/OBC and OBC-NCL should have scored minimum of 60% marks in aggregate or equivalent grade in the qualifying examination.
• Candidates belonging to SC/ST/PwD should have scored minimum of 55% marks in aggregate or equivalent grade in the qualifying examination.

I am assuming that you have mentioned your IISER exam marks. If you have scored 48 marks, then your percentage would be around 27%. Since you need more than 55% to get admission in your category, your chances of getting in are low.