There are multiple kinds of hostels available in India and the rules of every hostel differs in magnitude. For example, in the hostels of premier institutes like Indian Institute of Technology or IITs, there are very few restrictions, while in the hostels of private colleges like VIT or SRM, the restrictions are quite high, for example you cannot go outside of your hostel after say 8:00 pm.

So, depending on the hostel you get, the rules for mobile phones will become more clear. Hope I have answered your question. All the best!