Recent water analysis by the Delhi Pollution Control Committee (DPCC) reveals that the Shahdara, Barapullah, and Sen Nursing Home drains are the most polluted in Delhi. These drains are discharging untreated effluents directly into the Yamuna River. The report, dated September 9, highlights ongoing concerns about water quality in the region.
Among the drains from Haryana and Uttar Pradesh that indirectly contribute effluents to these drains, the L3 drain from Gurugram, which enters Najafgarh Jheel, and the Sahibabad drain from Uttar Pradesh fared the worst in terms of pollution parameters, with untreated sewage and industrial discharge. The monthly monitoring also covers six sub-drains with outfalls in the Agra Canal, three Uttar Pradesh drains with outfalls in the Shahdara drain, and sub-drains ending up in Najafgarh Jheel/drain. BOD indicates the level of organic pollution in water by measuring how much oxygen microorganisms need to break down the biodegradable component. COD measures the total oxygen required for the chemical oxidation of all organic and inorganic pollutants. Lower values indicate better water quality. None of the drains from which samples were collected in August met the BOD criterion. To be sure, in terms of the volume of wastewater discharge, the Najafgarh drain contributes the maximum amount of effluents to the river. Currently, the Delhi Jal Board (DJB) is unable to treat the entire amount of sewage generated by the city, and a large amount ends up entering the river.
TSS indicates turbidity levels due to undissolved components. There are 22 drains between Wazirabad and Okhla that directly discharge into the Yamuna, and eight of these drains were found to have no flow, while all the remaining 14 drains breached the prescribed standards for water quality. Under the current surveillance system, the government monitors water quality parameters such as Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Total Suspended Solids (TSS) from samples taken from 22 drains in Delhi. The standards for such drain samples stipulate that TSS should be less than 100 mg/L, COD less than 250 mg/L and BOD less than 30 mg/L. As per the DPCC August report on drain parameters, out of the 22 drains with direct outfalls, the Shahdara drain was the most polluted, breaching all parameters, with TSS of 240 mg/L, 2.4 times the maximum limit, COD of 272 mg/L and BOD of 120 mg/L, four times the maximum permissible limit. Shahdara was followed by the Barapullah drain, with TSS, COD and BOD of 218 mg/L, 256 mg/L and 120 mg/L, respectively. The Sen Nursing Home drain recorded these three parameters at 216 mg/L, 240 mg/L and 100 mg/L, respectively. The drain failed to meet the TSS (116 mg/L) and BOD (66 mg/L) parameters. The 22-km Yamuna stretch between Wazirabad and Okhla is the most polluted part of the river, with 22 major drains flowing into the river stream.
To increase its overall sewage treatment capacity, the Delhi government is connecting all households to sewerage treatment infrastructure, and a target to double the treatment capacity has been fixed for the next three years, officials said.
All three sub-drains — Banthala, Indrapuri and Sahibabad — fared extremely poorly. From Gurugram, the L3 drain was found to be adding the maximum pollution load to the Najafgarh wetland, which later ends up in the Najafgarh drain. Among the drains from Uttar Pradesh that indirectly add to the Yamuna’s woes, the Sahibabad drain fared the worst, with a Chemical Oxygen Demand of 284 units, worse than any other drain.
