KARACHI: Industrial waste from the factories of Nooriabad and Kotri industrial areas pose serious threat to Keenjhar Lake – the main source of water supply to Karachi, media reported on Tuesday. Toxic waste and polluted water used by factories being dumped into the Keenjhar lake without proper treatment since a long time now, sources said. Around 61 industrial units operational in two industrial zones, have not a single treatment plant to treat the industrial waste, according to local sources. The industrial waste of Nooriabad, which has been stored in the Kallu Khuhar Dam near Nooriabad, often flows downstream into Keenjhar when the water level rises in the dam, local people said. The effluents from the Kotri-based industries also dumped into the lake through the Kalri Baghar Feeder. The waste from Kotri industries flows into the Keenjhar lake throughout the year, while effluents from Nooriabad entered in the lake by the yearly torrential gush. It is to be pointed out that another major cause polluting the lake water is the waste dumped by tourists and visitors to the site as it is a major picnic point for people but it lacks proper management. “Several thousand people from Karachi visit the Keenjhar lake weekly,” a local official said..