Yes! You as a user are not meant to knowingly access data that does not belong to you. Even something like changing the id from 1 to 2 is legally considered unauthorised access.

It would be different if for example the application was showing data for other customers through normal use of it, but even if there is no other barrier to access than changing an id that is considered bypassing access control and can result in jail time in most places. Now I'm not an expert in India's computer misuse laws but I am willing to wager they are not the most progressive when it comes to this kind of thing.