Toxic PM2.5 Levels On October 31 Midnight 13% Higher Than Diwali Peaks In Last Two Years, Shows Analysis
Of the 38 air quality monitoring stations, PM2.5 concentrations exceeded the critical threshold of 900 µg/m³ in nine stations, indicating massive build-up of pollutants
Delhi breathed extremely toxic air on Diwali as PM2.5 concentrations peaked to dangerous levels of 603 micrograms per cubic metre (µg/m³) on the midnight of October 31. This was nearly 13 per cent higher than Diwali peaks observed in both 2022 and 2023, according to an analysis done by the Centre for Science & Environment (CSE).
Diwali was celebrated on October 24 in 2022, while it occurred on November 12 last year. The air quality across the national capital remained very poor over the last week with an average Air Quality Index (AQI) hovering between 300 to 390. The PM2.5 concentrations, however, rose steadily in the days leading up to Diwali.
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According to the latest analysis done by the New Delhi-based think tank, PM2.5 concentrations shot up by nearly 46 per cent from October 28 through October 31 — a time when bursting of firecrackers also hit a peak.
“Moreover, PM2.5 levels this year were more than twice as high as the average night-time pollution recorded over the seven nights before Diwali," according to the analysis led by Anumita Roychowdhury, Executive Director, CSE, along with environmental researcher Sharanjeet Kaur.
The Air Quality Forecasting system led by IITM Pune had also warned of severe levels of pollution on October 31 and November 1 due to additional emissions from firecrackers and stubble/waste fires. Worryingly, the pollution levels were also high during the day on Diwali, with PM2.5 nearly 92 per cent higher than last year’s Diwali daytime average, indicating high levels of local and regional pollution this year aided by sharp increase in farm fires.
WHERE WERE THE HOTSPOTS?
Of the 38 air quality monitoring stations, PM2.5 concentrations exceeded the critical threshold of 900 µg/m³ in nine stations, indicating massive build-up of pollutants on Diwali night. The highest levels were observed at Nehru Nagar (994 µg/m³), Anand Vihar (992 µg/m³), Pusa IMD (985 µg/m³), Wazirpur (980 µg/m³), and JLN Stadium (963 µg/m³).
Not just PM2.5, this year Diwali night also recorded higher NO2 levels compared to last year, indicating higher congestion on the road and traffic conditions leading to the festival night. According to researchers, NO2 levels in the last three years have been higher on Diwali night and also the nights preceding it.
WARM WEATHER CAME AS A RELIEF
The India Meteorological Department (IMD) confirmed October 2024 to be the warmest October since 1901. As a matter of relief, this relatively warm weather and adequate winds helped in quicker dissipation of the pollutants compared to previous years and did not lead to a smog episode, which occurs when AQI remains ‘severe’ for at least three consecutive days.
The AQI was ‘’poor’’ on the afternoon of October 31, hit the ‘severe’ levels by midnight and remained high until early hours of November 1. It gradually decreased to moderate levels by afternoon. This prevented a deadly smog episode this Diwali. But the air pollution in Delhi is expected to worsen over the coming days as temperatures fall.
SHARP INCREASE IN FARM FIRES
There was a sudden and sharp escalation in farm fire count on the day of Diwali and since the winds were north-westerly, it increased the share of its contribution to Delhi’s air quality by 27 per cent.
According to data from the Indian Agricultural Research Institute (IARI), the fire count increased from 380 on October 30 to 605 on October 31, and 983 on November 1. Punjab accounted for the highest share (80 per cent), followed by Uttar Pradesh (13 per cent), and Haryana (7 per cent).
Experts also highlighted that the air quality of Delhi has turned from ‘poor’ to ‘very poor’ even when the share of smoke from farm fires was less than 1-3 per cent this season. “This brings out the high impact of local air pollution sources that require urgent mitigation at scale and with speed," said CSE.
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