In the forest on both sides of Tughlaqabad Fort’s southern outer wall, a lake has slowly materialised over the past two years. Leafless tree-trunks jut out at odd angles from the poisonous water. Sludge and plastic bags gather at its banks.
A team from the Ministry of Environment and Forest said the water was “contaminated”. This is an understatement. Biochemical oxygen demand (BOD) — commonly used to measure the toxicity of a water body — was found to be over four-times the prescribed 30 mg/litre at 138 mg/litre. Chemical oxygen demand (COD) — indicative of the presence of organic compounds — was found to be 619 milligram mg/l. The prescribed COD limit is 250 mg/l.
The ministry team came to examine the water’s toxicity after an order from the High Court, following the PIL filed by lawyer and resident Sushil Kumar. “The lake began forming slowly two years ago. It is covered in algae. Today, its impact is apparent. The monkey population has reduced. Herds of Nilgai came here earlier, but they have stopped coming. People have fallen sick,” he said.
Kumar said the lake has at least three distinct sources — a natural drain that previously carried rainwater into larger canals, a sewer that carried out waste from Tughlaqabad village and a larger drain that, residents say, carries chemical effluents from illegal industries existing within the village. This was confirmed by the environment ministry, which told the court that the concentration of pollutants could be a result of “discharge from unsewered areas or industrial activities in the vicinity”.
The water body begins at the southern tip of Tughlaqabad village, adjacent to a slum occupied mostly by migrants, flows under the abandoned fort’s outer wall and into the low-lying DDA forest land on the other side of the wall. The water has submerged a number of trees in the area, killing them. “Earlier, this was a small stream, mostly rain-fed. But its natural drainage path has been blocked due to plastic waste and debris from illegal construction,” Kumar said.
The slum, near the lake’s origin point in the village has a number of houses which are under construction. Sonu, who migrated to Delhi from Madhya Pradesh four-years ago said, “The water here is so polluted that we get water — for drinking and washing — from outside. Not even insects can survive here. Some times children fall in and develop rashes.”
While the ministry in its affidavit claimed that the “lake” is 2km long, residents pointed to smaller inter-connected pools of accumulated waste water spread across the DDA forest land. “The officials were notified about the water, once is began accumulating. But we heard nothing else,” a DDA official, in charge of the forest’s maintenance, said.