Hi Writabrita Bhattacharya !

There is no release of official cutoff, the observations are made based on the marks obtained after students see the answer key.

In 2019 the cutoff for Unreserved category was 88–90 and EWS was around 84 ,this time considering the increasing seats by 20% and the intake through SCB channel in about 75% increase, it's possible that the cutoff further reduce to around 76–80 marks .But it also depends on the level of difficulty of this year's IAT as compared to 2019. Turns out that the IAT 2020 was at par as compared to 2019.

Still, 60 gives a fairly low chance while 80 is somewhat safe whereas 70 stand in between.

Nevertheless, don't loose hope and keep checking your emails for updates. Be patient till the last rounds of allotment (there may be chances to get seat in the newest IISERs i.e Tirupati and Berhampur). It also depends on your list of preferences. There may be post allotment rounds so it is requested to be patient till the last.

All the best !