A decades-old dispute between India and Bangladesh revolves around the distribution of the waters of the transboundary Teesta River. Bangladesh wants a larger share than it currently has and is pushing for a billion-dollar megaproject to go ahead. But relations between Dhaka and New Delhi are at an all-time low since the ousting of former prime minister Sheikh Hasina in August. So what's holding up the project? Why is the Indian state of West Bengal opposed to it? And how is China involved?