Are exams at IIT Bombay tough?

Yes, exams conducted at IIT Bombay are quite tough given the competition at the institute. The exams usually test your understanding capabilities and not your learning capabilities.

I did one subject which was very difficult and involved a project demonstration in the end. But the professors teach the topics so well that you hardly have to mug up the concepts. 

Once the exams were conducted in a unique manner wherein, 

• The students were allowed to open books as they were not able to solve the paper
• The students requested the professor to extend the duration from 3 hrs to 5 hrs after which the students still could not finish the paper.
• The students were then asked to take the paper home and were given 7 days to prepare for the presentation on the same. 

The game changed its course and because marks were not to be allotted on the basis of the presentation everyone prepared the concepts well and attended the open contest.