There is no such dress code for first-year students. However, you are asked to wear formals during practical exams and on occasions like function/party.
On the other hand, there are lots of restrictions on the dress code of girls.
For boys, there are no such restrictions but that doesn’t allow them to walk in shorts in premises.
To be more accurate every day students wear jeans and T-shirt on a normal basis. Yes, sometimes seniors do expect you to be in formals and you should listen to them. But so far there are no rules for specifically wearing formals. You can wear what you feel comfortable in.