Hi Sourav.

There are a number of undergraduate programmes for Geography after class 12 from any board.
But the discipline will get divided into Human and Physical Geography, so you might have to choose one of the two, but some colleges also provide both simultaneously.

If you are serious about Geography, do apply to Delhi University's Kirori Mal College. It is one of the few colleges in DU to provide Geography. Otherwise, you can apply to Xavier's Mumbai, Loyola Chennai and MCC Chennai.

Good luck.