Upper Lake considered to be the lifeline of the state capital is dying a slow death. A large part of the city’s sewage, chemical and toxic waste finds its way into the millennia old water body, degrading its quality. Each day, the Upper Lake which is source of drinking water for 40% of the city is filled with some 7,500 cubic metric million litre of sewage. Treatment plants that handle the task of sewage filtration do exist, but environmentalists question the effectiveness. “The sewage treatment plants are not in line with the capacity requirement. These can only filter water not the chemicals,” says environment activist, Subhas C Pandey. A senior government scientist, during a discussion on air pollution in the city, warned that the unchecked sewage that is flowing in the Upper Lake is causing drastic water quality degradation. The only man-made lake mentioned in the list of Ramsar sites under the Ramsar Conversation on Wetland, Upper Lake, is also the only one on the list that doubles as a source of drinking water. The degeneration of water quality is enhanced by unabated flow of sewage mixed with storm water run-off into the lake. “As the lake fills up, the mean depth and detention time of the water body decreases. Excessive plant growth like green colour, decreased transparency, excessive weeds are all signs of degradation,” added the scientist. The Bhoj Wetland Project a large area of around 33.78 square km has had severe weed infestation in the entire fringe area.