Pollution in Delhi soar 68% within 24hrs: CSE Report

Delhi experienced a sudden and significant spike in pollution levels on November 2, with PM2.5 concentration levels soaring by 68% within 24 hours, crossing the ‘severe+’ category as per the Air Quality Index (AQI) concentration range. The analysis released by the Centre for Science and Environment (CSE) in response to the deadly winter pollution currently gripping Delhi-NCR.

Anumita Roychowdhury, executive director of research and advocacy at CSE, stated that this winter season has begun with much higher pollution levels compared to November last year. The combination of adverse meteorological conditions, onset of crop residue burning, and high local pollution has dangerously tipped the scale, increasing public health risk.

Roychowdhury added that even though the overall long-term pollution curve is stable and downward, it is still significantly above the national ambient air quality standards. This situation demands the most stringent and sustained action on vehicles, industry, energy systems, and waste management across the region.

Sudden Smog Increase in Delhi

The analysis, conducted by CSE’s Urban Lab, highlights the sudden and rapid build-up of smog in the early phase of winter. On November 2, PM2.5 levels in Delhi crossed the ‘severe+’ level for the first time this season, marking a sudden escalation of 68% within 24 hours.

Avikal Somvanshi, head of CSE’s Urban Lab, noted that such rapid build-up is not uncommon during this part of the season and is generally associated with smoke from farm stubble fires and meteorological factors assisting the transportation of smoke to Delhi-NCR. However, he emphasized that the rapid build-up in a short time span is able to tip air quality into the severe category because baseline pollution from local sources is already very high.

The report also highlights that heatwaves exacerbate air pollution, which already causes an estimated 7 million premature deaths every year and stands as the fourth biggest killer by health risk factor. The share of PM2.5 in PM10, an important indicator of the impact of combustion sources, has crossed 50%, indicating a higher impact of combustion sources.

The analysis underscores the urgent need for stringent and sustained action on vehicles, industry, energy systems, and waste management across the region to mitigate the health risks of climate change.

Delhi’s pollution levels soar as winter begins

Delhi experienced a sudden and significant increase in pollution levels on November 2. Consequently, PM2.5 concentration levels rose by 68% within a mere 24-hour span. This abrupt surge pushed the air quality into the 'severe+' category, as defined by the Air Quality Index (AQI) concentration range.

One notable trend observed this year is the abrupt and rapid accumulation of smog in the early phase of winter. On November 2, PM2.5 levels in Delhi crossed the 'severe+' threshold for the first time this season, indicating a remarkable escalation within just 24 hours.

In terms of pollution hotspots, New Moti Bagh, Nehru Nagar, Sonia Vihar, and DU North Campus have emerged as the latest areas suffering from the worst pollution in Delhi. Meanwhile, Greater Noida, Noida Sector 62, Loni, and Faridabad in the National Capital Region (NCR) continue to grapple with high pollution levels.

When it comes to nitrogen dioxide (NO2) pollution, the most polluted location in Delhi is ITO, with an average of 219 µg/m3. Nehru Nagar and Siri Fort closely follow as the next most polluted NO2 locations in the city.

Comparatively, Delhi's official PM2.5 hotspots exhibit lower levels of NO2 pollution. In the broader NCR region, Noida Sector 125 and Sector 1, along with Ghaziabad's Sanjay Nagar and Indirapuram, rank as the areas with the highest levels of NO2 pollution.

Early PM2.5 rise, increased combustion impact

This year, the levels started to rise from the middle of September, which is earlier than the previous five years when PM2.5 levels started to rise steadily from the beginning of October. This increase was at a slower rate and by the end of October, the levels were 20-30 per cent lower than the average levels for the corresponding Octobers of the previous five winters – since 2018-19.

The share of PM2.5 in PM10, an important indicator of the impact of combustion sources, has crossed 50%, indicating a higher impact of combustion sources. On November 2, the ratio for PM2.5 stood at 60 per cent – highest this season indicating the higher influence of combustion sources.

The analysis also highlights that heatwaves exacerbate air pollution, which already causes an estimated 7 million premature deaths every year and stands as the fourth biggest killer by health risk factor.

The report underscores the urgent need for stringent and sustained action on vehicles, industry, energy systems, and waste management across the region to mitigate the health risks of climate change.

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