Yamuna pollution affecting birds at Okhla: Forest dept
The Gautam Budh Nagar forest department has urged the irrigation department of the Delhi government to ensure that sewage generated in the national capital is treated before being discharged in Yamuna, stating that the “excessive pollution” in the river is causing adverse impact on avifauna at the Okhla Bird Sanctuary (OBS).
Officials from the forest department have said the number of migrant birds at the sanctuary -- situated downstream of Yamuna -- has dropped due to the pollution in the river. They suggested to the Delhi irrigation department to build sewage treatment plants to minimise the “adverse impact” on the habitat health.
The officials said that while the forest department is yet to get the water samples from sanctuary tested to assess its quality, the wetland has started to stink and the presence of oil and grease in the water is visible.
“Thousands of migrant birds arrive at the 400-hectare lake in the Okhla Bird Sanctuary. Sewage from several drains is released every day into Yamuna causing adverse impact on the birds here. Due to the excessive pollution in the river, the birds are leaving the sanctuary. It is thus requested to ensure that all the drains are treated using sewage treatment plants prior to their release in the river so that waterbirds are not affected,” PK Srivastava, divisional forest officer, GB Nagar, has said in a letter (dated February 22) to the Delhi irrigation department.
According to the Asian Waterbird Census-2021, the number of birds at OBS went down to 8,068 against 8,776 last year and 12,212 in 2019.
The water quality of the river around Okhla barrage has been worsening. As per the Delhi Pollution Control Committee’s (DPCC’S) report, the dissolved oxygen (DO) levels in Yamuna are nil since 2018. The DPCC report also pointed out that biochemical oxygen demand (BOD), the minimum oxygen levels required to decompose the chemicals present in the water was ten times the standards in November 2020. The UP forest department also in February last year had the water samples from the sanctuary tested and found that the DO levels at the sanctuary were well below the required norms.
The BOD at OBS in February 2020 was 14mg/l while at Okhla barrage it was 58 mg/l in the same month, against the standard limit of 3 mg/l.
Spread over 400 hectares, of which 80% is water body formed due to the Okhla barrage build over Yamuna river, the Okhla Bird Sanctuary is home to a number of water and terrestrial birds and is Noida’s only ecosensitive zone.
“There is no source of pollution in the sanctuary. There are about 19 drains in Delhi which release effluents directly into the Yamuna and the pollutants reach here without being treated. Due to this, the wetland’s water is polluted,” said Arvind Mishra, regional forest officer at the sanctuary.
Officials of the Delhi irrigation department could not be contacted despite repeated attempts.
Stating that healthy bird population is a direct indicator of the habitat health, Delhi-based conservationist Bikram Grewal stated that water quality has direct impact on the bird population.
“If the water is polluted due to presence of chemicals, oil, etc., then it will definitely have impact on the avifauna especially the waterbirds. Due to high level of pollution in Yamuna, there are several indicator bird species which are not seen anymore. Now, we don’t see species like skimmer and osprey, which is an eagle that fishes in fresh water, around Delhi,” said Grewal.
Environment activist and Manoj Mishra, convener of the Yamuna Jiye Abhiyan, an organisation founded to revive and protect the river and its floodplains, said that Yamuna after Wazirabad in Delhi is “nothing but a lifeless nallah”.
“The water that one sees at the Okhla sanctuary is not Yamunua’s water but is sewage being generated from houses and industries of Delhi. Question is how much someone would treat a sewage. The river is anyways lifeless because it still continues to receive untreated sewage and effluents,” said Mishra.