The Delhi Pollution Control Committee (DPCC) has released a report indicating that the quality of water in the Yamuna River has improved along the Delhi stretch in comparison to April 2019. The study, conducted in collaboration with the Central Pollution Control Board (CPCB), was prompted by an inquiry from a National Green Tribunal (NGT) appointed monitoring committee. This improvement follows earlier observations of reduced air pollution and enhanced air quality in various cities.
Data Analysis Highlights
The DPCC’s study involved collecting water samples from nine locations along the Yamuna River and twenty drain locations. These samples were examined and compared with data from April 2019. The findings revealed a reduction in pollution levels ranging from 18% to 21% at different locations. Five sites reported a decrease in Biochemical Oxygen Demand (BOD) levels between 18% to 33%, while other areas showed slight to notable increases. Four of the nine areas where dissolved oxygen (DO) was non-existent in 2019 reported DO levels between 2.3-4.8 mg/l in 2020. Despite these improvements, the Yamuna’s water quality has yet to meet the established “water quality criteria”.
Main Factors for Improvement
The lockdown strategy enforced to mitigate the COVID-19 pandemic was one of the reasons behind the better water quality. According to a previous report by the Delhi Jal Board (DJB), the lockdown had a positive impact on water quality. In addition, Haryana increased its water discharge, which further diluted pollution due to the inflow of fresh water.
Understanding Biochemical Oxygen Demand (BOD)
BOD refers to the amount of dissolved oxygen required by microorganisms to decompose organic waste or pollutants under aerobic conditions. A high BOD level indicates more oxygen is needed to decompose substantial quantities of organic matter present in the water, implying higher levels of pollution. One of the key reasons for treating wastewater before releasing it into a water body is to lower its BOD, reducing its oxygen demand, and lessening its impact on streams, lakes, rivers, or estuaries.
Significance of Dissolved Oxygen (DO)
DO is the amount of oxygen dissolved in water which is essential for aquatic life. Water quality improves as DO increases. A DO level of 5 mg/l or more is recommended for bathing in a river.
About Yamuna River
The Yamuna River, a primary tributary of river Ganges, originates from the Yamunotri glacier near Bandarpoonch peaks in the Mussoorie range of the lower Himalayas in Uttarakhand. The river meets the Ganges at the Sangam (the site of the Kumbh Mela) in Prayagraj, Uttar Pradesh, after flowing through Uttarakhand, Himachal Pradesh, Haryana, and Delhi. The river runs approximately 1376 km, with significant dams such as Lakhwar-Vyasi Dam (Uttarakhand), Tajewala Barrage Dam (Haryana), and notable tributaries including the Chambal, Sindh, Betwa, and Ken.
