I had a brief phone interview. I had already been nearly accepted, I think they just wanted to gauge that I was a good fit and was excited about joining their department. All in all, I don't think the interview was a big part of the application process.

If you clear the first round of selections (at least for the Chemistry dept) then they take an interview to determine your fluency in English. The questions are based on you, your interests, your academic inclinations and etc., it is a non technical interview