The Central Pollution Control Board (CPCB) recently released a report indicating that the pollution level in the Ganga River has not seen a significant decrease during the lockdown period. The Ganga, one of India’s major rivers, was evaluated for pollution levels a week before and weeks after the enforcement of lockdown at 36 locations across Uttar Pradesh and West Bengal.
The Assessment Data
According to the CPCB’s findings, the Dissolved Oxygen (DO) level in the river did see a slight improvement. However, Biological Oxygen Demand (BOD) levels observed an upward trajectory, especially in the downstream areas in the river with maximum values being reported in West Bengal. On the bright side, there was a small reduction in Chemical Oxygen Demand (COD) levels which is said to be due to the halt in industrial activities during the lockdown. Disturbingly, the highest pollution levels in the Ganga were recorded in Uttar Pradesh.
Primary Sources of Pollution
The main perpetrators behind the Ganga’s pollution are domestic wastewater produced by 97 towns situated along the river and industrial effluents released into the river. Interestingly, improvements were noted in the water quality of the Yamuna River during this period.
About Dissolved Oxygen (DO)
Dissolved Oxygen characterizes the quantity of freely available oxygen present in any water body. Factors like surface turbulence, photosynthetic activity, oxygen consumption by organisms, and decomposition of organic matter, determine DO levels. Undoubtedly, higher DO levels signify better water quality.
Understanding Biochemical Oxygen Demand (BOD)
BOD is a parameter used to measure pollution caused by organic waste in bodies of water. It signifies the volume of dissolved oxygen that bacteria need to decompose the present organic wastes in water. Therefore, a higher BOD value indicates a lower DO level. However, BOD is limited to biodegradable materials, making it an unreliable method for measuring overall water pollution.
About Chemical Oxygen Demand (COD)
COD measures the quantity of oxygen, in parts per million, required to oxidize both biodegradable and non-biodegradable organic compounds and oxidizable inorganic substances present in a water sample.
Exploring The Ganga River System
The primary source of the Ganga River is the ‘Bhagirathi’, which is nourished by the Gangotri Glacier and later joined by the Alaknanda at Devprayag, Uttarakhand. The river flows out from the mountains to the plains at Haridwar. Several tributaries join the Ganga, including major rivers like the Yamuna, Ghaghara, Gandak, and Kosi. At Farakka Barrage, the Ganga splits into two; one part, the Bhagirathi-Hooghly, flows southward into the Bay of Bengal whereas the mainstream river heads towards Bangladesh, merging with the Brahmaputra and forming the Sunderbans Delta.
Role of the Central Pollution Control Board
The Central Pollution Control Board, a statutory body under the Ministry of Environment, Forest and Climate Change, was established in 1974 under the Water (Prevention and Control of Pollution) Act. Its responsibilities also encompass powers and functions under the Air (Prevention and Control of Pollution) Act, 1981.
