I applied through university. The process took 1 day. I interviewed at Indian Institute of Technology Bombay (Mumbai) in Aug 2017
Interview
You have to apply for the subjects you want to be the TA for and meet the professor before hand or you should have taken the course in your undergrad or post grad.
Interview questions [1]
Question 1
What is your current CPI and any background knowledge of the subject?
I interviewed at Indian Institute of Technology Bombay
Interview
For GNR, IIT B they shortlist the students based on Gate cutoff and then call for an interview, the weightage for interview score is 30% and Gate score is 70% based on that after all the process admission result will be released on COAPS portal.
Interview questions [1]
Question 1
Intro
Btech final project
Intership experience (if any)
any favourite subject (ques on that)
basic Calculus,
I interviewed at Indian Institute of Technology Bombay
Interview
Quizzed on basics of biotechnology. Quizzed by a panel of 5 professors. Showing your thinking process is crucial. It helped that my academic record was very good. Panel was reasonable, did not grill me too much when I didn't know the answer.