All colleges, specially in India, will not give an environment to Open source. There are certain colleges those support OSS but not all. If you want to get involved in a project and want to contribute code, it will completely depend on your preference of language. Which languages do you know? Which of them do you prefer? Sourceforge is a good place to start off with. There are estnormous projects listed there which need contributions from volunteers. Go there and search. Find out which are the project which need contribution. If some project excites you, get the code for that and study. Find out if you can improve the code or remove bugs listed. Test it and file the bugs. Testing is also a means of contributing to the project. If you have an idea in your mind and do not see anything related to that in sourceforge, start your own project.
And if you own a computer or laptop, load linux on it and use it for day to day activities.