How is the physics department at IISER Kolkata?

The Physics department of IISER Kolkata is the best among all the other IISER. It is also the best department among all the departments of the institute, in terms of quality of academics, faculties, research outreach, and management. 

However, you should note that just joining IISER Kolkata, does not necessarily mean that you will get Physics as your major. You will need to maintain a decent percentile till your 2nd year to get Physics as your major.