Rather than just academics, IIM Ahmedabad students are interviewed on an overall basis. That is various aspects like extracurricular activities, leadership skills and behaviour management are also tested in the interview round.
Social clubs and college societies are also a part of your interview. But not the most important part though. Some might get selected even without much involvement in clubs while some might not get selected even with much involvement in the same.
You usually are asked about your hobbies to which you can simply answer anything you like doing in your leisure time. It can be as simple as reading novels also. More than anything your confidence while answering the question matters the most.