Hello Richa yadav  ,

For IISER, Category wise class 10+2 CBSE board cutoff is :

GENERAL : 431/500

OBC-NCL : 420/500

SC : 401/500

ST : 385 /500

PwD : 385/500

And apart from that, you need to appear for IISER Aptitude test (IAT) which is conducted all over India in various states and if you qualify that according to the cutoffs then only you will be eligible for admission in IISERs.

Hope that helps!