IIM Ahmedabad students just need a laptop that can run Microsoft Office and multitask. An Intel Core i5 or i7 laptop with at least 8GB of RAM is recommended. Since as a student there you will need to use your laptop in class and for studying, so go for a laptop with long battery life.
You can have a laptop case, mouse, and external hard drive for backups. Online classes and video conferencing may benefit from a decent headset or noise-canceling headphones. As you will need to type a lot so you can have an external keyword as well.
Check the college's official rules and recommendations for allowing or not allowing electronic devices, or any other accessories.