Generally you can't change your major without changing your college and starting over (or at least from year 2) so it's almost never done. I saw a thread on Reddit the other day where someone explained the Russian system and it sounds similar to what we have in India:
"Majors/minors. It's such a big deal in a lot of fiction, for example. But even though I read about it a lot of times, I still don't quite get it, along with class selection. In Russia, you choose a specialization when you enroll (e.g. Applied Math), and from the day one to the end, all students in your group will attend the same classes and take the same tests and exams. American system seems like a computer game's research tree to me - "you must unlock A, B and C before studying D", and somehow, it's your burden to keep track of what classes you attended and got grades in. WTF. Here, you just get a ready-made complete curriculum, no need to do anything but study. If you feel you chose a wrong specialization in the beginning, you might change it, and then things become a bit complicated, but it only happens rarely, and usually only right after the first semester." [1]
https://www.reddit.com/r/AskReddit/comments/8qrh78/nonameric...