A file photo shows Durga idols floating at the Yamuna. (Photo: PTI)
The idols immersed during Dussehra has plummeted the dissolved oxygen (DO) level in Yamuna to zero in the river’s journey through the national capital, a Delhi Pollution Control Committee (DPCC) study has found. The DO supports aquatic life in the river.
The recent idol immersions have resulted in high levels of Biochemical Oxygen Demand (BOD), that indicates the level of organic pollution, the report says. A waterbody has to have a minimum 4 mg/l of DO, while the BOD should not exceed 3 mg/l for aquatic life to thrive, according to the DPCC.
But the study, commissioned to assess the water quality of Yamuna on the occasion of Dussehra, has found that BOD saw a steep rise of 38 mg/l at Kudesia ghat during immersions, where DO was zero.
The DO was found to be zero across Yamuna ghats on October 11. Only at Shyam ghat it had a 2.1 mg/l presence, down from 6.1 mg/l the previous day, the study says. At Shyam Ghat, Geeta Ghat, Mayur Vihar’s Chhath ghat, Haathi Ghat and Kalindi Ghat, the BOD was recorded at 12, 25, 19, 33, 28 mg/l respectively on October 11. On October 9, the respective levels were 8, 20, 13, 24 and 20 mg/l.
In a 2015 report, the Central Pollution Control Board (CPCB) had identified unabated discharges of wastewater into Yamuna, predominantly from domestic sources. The wastewater is responsible for its deteriorating water quality, especially in its stretch after Wazirabad barrage, as per the CPCB. 0
“The other reason is the non-availability of fresh water in the river after Wazirabad barrage, which is essential to maintain self-purification capacity,” it said.
Based on the discharge and BOD load of 18 drains that join Yamuna in Delhi, Najafgarh drain was found to be the biggest polluter, followed by the Shahadara drain.
