You know Pawan I just went to the parking lot to see what the possible places of a leak can be. Check the following:
1) The rubber beading where the door meets the roof. The rubber possible has worn out. (Rubber wearing out can cause many leaks and troubles you see
).
2) Once you open the door there are two drain holes in the rear door, check if they are clogged.
3) Any gaps in the window frame?
Let me know.