Hiii, thank you for choosing Careers360.

IISER has its own eligibility criteria. You can get on the basis on any one of these three.

Through KVPY, if your fellowship is of 2019-2020, JEE advanced 2019: if you qualify the limited rank set by them or SCB: for that you should've cleared 12in 2018 or 2019.

So, you can't got through the other two. You can see for yourself in the other two criterias.

Hope this helps!