A dredger at work in the Ganga river. Photo: Mayukh Dey
New Delhi: The water quality of five major rivers in the country, including the Ganga, deteriorated during the coronavirus-induced lockdown due to factors like the release of sewage and no upstream freshwater inflows, the Central Pollution Control Board said on Wednesday.
The water quality of the Ganga, Beas, Chambal, Sutlej and Swarnarekha rivers did not comply with the primary water quality criteria for outdoor bathing, the pollution watchdog said in a report released on the occasion of its 46th founders’ day.
According to the report, titled ‘Assessment of Impact of Lockdown on Water Quality of Major Rivers’, the quality of water in seven of the 19 rivers monitored by State Pollution Control Boards (SPCBs) improved during the lockdown period.
The CPCB said it had asked the SPCBs to assess the water quality of Ganga, Yamuna, Godavari, Krishna, Narmada, Beas, Brahmaputra, Baitarani, Brahmani, Cauvery, Chambal, Ghaggar, Mahanadi, Mahi, Pennar, Sabarmati, Sutlej, Swarnarekha and Tapi. Twenty SPCBs participated in the assessment.
Water samples collected from the 19 rivers were analysed for parameters like pH, Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD) and faecal coliform. According to The Hindu, BOD can help determine the extent of microbial life, while the DO can help judge the effect of organic pollutants. The pH levels denote the acidity of the water and faecal coliform are the microbes that come from human and animal waste.
For the water to be considered fit for bathing, a river’s BOD must be less than 3 milligram per litre, while its DO level should be greater than 5 milligram per litre. Its pH levels should be between 6.5 and 8.5, while the levels of faecal coliform should be less than 2500 per 100 millilitre.
The results were then compared with the Primary Water Quality Criteria for Outdoor Bathing notified under the Environment (Protection) Rules, 1986.
“Water quality has not improved during the lockdown period in case of five rivers which are Beas (reduced from 100 to 95.45%), Chambal (reduced compliance to the criteria limits from 75 to 46.15%), Ganga (reduced compliance to the criteria limits from 64.6% to 46.2%), Sutlej (reduction in compliance from 87.1 to 78.3%) and Swarnarekha (reduction in compliance from 80 to 53.33%),” the report said.
This may be attributed to discharge of untreated or partially treated sewage, high pollutant concentrations due to negligible dry season flow and no freshwater discharges from the upstream, it said.
According to the report, river water samples from 387 monitoring locations were collected during the pre-lockdown period and 77.26% of them complied with the primary water quality criteria for outdoor bathing.
During the lockdown, 365 samples were collected and 75.89% of them complied with the criteria, “which implies that there is no significant improvement in water quality of major rivers monitored in the country, during the lockdown period”.
What the data shows
Four rivers – Baitarani, Mahanadi, Narmada and Pennar – showed 100% compliance with the Primary Water Quality Criteria for outdoor bathing during the pre-lockdown and lockdown period.
The water quality of river Ghaggar did not comply with the criteria.
The water quality of the Sabarmati and Mahi rivers remained unchanged at 55.6% and 92.9%, respectively.
Improvement was seen in the water quality of Brahmani, Brahmaputra, Cauvery, Godavari, Krishna, Tapi and Yamuna.
Brahmani’s compliance with the bathing criteria increased from 85 to 100%, Brahmaputra’s from 87.5 to 100%, Cauvery from 90.5 to 96.97%, the Godavari from 65.8 to 78.4%, Krishna from 84.6 to 94.4%, Tapi from 77.8 to 87.5% and the Yamuna from 42.8 to 66.67%, the report stated.
The report attributed this improvement in the water quality of the rivers to minimal industrial effluent discharges in view of the closure of almost all industries, no human activities involving the disposal of puja materials and garbage during the lockdown period.
No anthropogenic activities such as outdoor bathing, washing of clothes, vehicle washing and cattle washing, no pilgrimage activities, and considerably reduced cattle movement also played a role in reducing contamination of water bodies, the report said.
After initial reports said that the lockdown had helped improve the water quality of the Ganga, writing in The Wire Science, groundwater engineer K.A.S. Mani explained why flagship programmes such as the ‘Namami Gange’ have not shown significant progress. He wrote:
“The greatest flaw in [Namami Gange] and similar programmes is that we set out to clean a river system that already works well, just that we keep polluting it with industrial effluents, sewage and plastic. Instead of protecting rivers by blocking pollutants from entering them, we decided to continue polluting them and cleaning them at the same time.”
‘Drastic improvement in air quality’
Another report released by the CPCB found that the air pollution levels in many cities fell drastically after the lockdown was imposed. It observed an improvement in the Air Quality Index (AQI) of Delhi and its neighbouring towns of Faridabad, Gurugram, Noida and Ghaziabad as well as in Mumbai, Bengaluru, Kolkata, Chennai, Indore, Patna and Singrauli.
According to the Indian Express, the air quality data was studied by the body in three stages – pre-lockdown (March 1-21), lockdown phase-I (March 25-April 19) and lockdown phase-II (April 20-May 3). This data was compared to the corresponding time periods of the previous year to analyse the improvement in air quality.
The analysis shows that PM2.5 levels fell by 16% due to the lockdown regionally, but the improvement was far higher in urban areas. “With transportation, industries, commercial activities, construction etc halting in cities, the air quality showed an improvement. But a similar impact was not felt in rural India,” the IE report says.
(With PTI inputs)