Hello Geethika,

I would like to mention the eligibility criteria for IISER below taken from the official website:

Candidates who have passed 10+2 or equivalent level exam with science stream in 2018 or 2019 are eligible to apply for admissions. Candidates will be admitted to IISER only through following three channels.

• Kishore Vaigyanik Protsahan Yojana (KVPY) channel
• Joint Entrance Examination (JEE-Advanced) of the Indian Institutes of Technology
• State and Central Boards Channel (SCB)

These channels will be referred to as KVPY, JEE, and SCB, respectively.

Indian nationals and students belonging to PIO or OCI category are eligible to apply provided they satisfy the eligibility criteria described below.

KVPY Channel

• Candidates having a valid KVPY fellowship commencing from 2019-20 academic session are eligible to apply for admissions. Additional cut-off criteria for marks obtained in 10+2 board examination is also applicable. Please see the cut-off criteria here.

JEE-Advanced Channel

• Candidates in General category securing a rank within 10000 in the Common Rank List (CRL) of JEE Advanced 2019 are eligible to apply. For candidates belonging to the reserved category (OBC-NC, SC, ST, PD), their category rank should be within 10000. Additional cut-off criteria for marks obtained in 10+2 board examination is also applicable. Please see the cut-off criteria here.

SCB Channel

• Students who have passed 10+2 level with science stream in 2018 or 2019 are eligible to apply for admissions and appear for IAT 2019.
• However, they will be considered for admissions to the degree programmes only if they obtain the cut-off marks specified 

For more info, please visit the website below.

The link is: https://www.iiseradmission.in/eligibility/

Hope this helps!