Varanasi meets air quality standards: Analysis

New Delhi: Varanasi is among seven cities that met national standards for PM2.5 in the winter of 2022-23 and 2023-24, an analysis said on Tuesday.

New Delhi-based Climate Trends' analysis has reflected on PM2.5 level trends during the previous season of winter for the past two years in seven major cities in India.

Fine particulate matter is particles that are 2.5 microns or less in diameter (PM2.5).

Varanasi made progress despite being part of the Indo-Gangetic Plain region, which is the most polluted in India, it said.

Besides Varanasi, the other cities are New Delhi, Mumbai, Chandigarh, Patna, Kolkata and Lucknow.

Despite focused attention on the national capital, PM2.5 levels in Delhi saw an increase in the winter months of 2023-2024 compared to the previous year.

During the winter period (October-February), January and February see lower pollution levels across the cities (except Chandigarh) than in October to December despite lower temperatures.

This could result from other meteorological factors like wind speeds and fewer sources like crop burning in some states in northern India.

In the winter of 2023-24, there was much uproar over Mumbai's poor air quality days, but data shows that PM 2.5 levels in the city were lower this winter vis-a-vis 2022-2023.

An in-depth analysis is required to understand the improved levels in some cities so that similar measures can be implemented in other cities too, it says.

Air pollution poses a significant global environmental and public health challenge, adversely impacting human health, ecosystems, and the economy.

Air pollution is a pressing concern in densely populated urban areas like major cities in India, particularly during winter when pollution levels often reach hazardous levels.

Winter pollution is exacerbated by various factors, including temperature inversions, stagnant atmospheric conditions, increased emissions from heating sources, and accumulating pollutants over time. These conditions lead to elevated concentrations of PM2.5 and other pollutants, posing serious health risks to residents, especially vulnerable populations such as children, the elderly, and individuals with pre-existing health conditions.

The PM2.5 concentration in Delhi exhibits significant fluctuations over time, with values ranging from relatively low (9.46) to very high (405.24) levels.

The data suggests that certain months experience consistently higher or lower PM2.5 levels than others, possibly influenced by monthly factors or external events.

Despite fluctuations, there seems to be a general increasing trend in PM2.5 concentration over the observed period, especially noticeable in the later months.

In Chandigarh, based on the daily average PM2.5 concentration data spanning from October 1, 2022, to February 28, 2024, there was significant fluctuations over time, with values ranging from relatively low (11.24) to very high (283.26) levels.

The data suggests that the trend is not consistent. Most of the day pollution levels exceeded the national standard. Mid-December and January were the most polluted months.

Responding to the analysis, Sagnik Dey, Associate Professor, Center for Atmospheric Sciences, IIT-Delhi, said, "Although cities show promising results, we need to demonstrate how much of the observed changes in PM2.5 can be attributed to reduced emission from local sources after incorporating meteorological impacts.

"Further deep dive is required to dissect the data in terms of local and regional factors."