As Diwali approaches, so does the conversation about pollution in New Delhi. A day after Diwali, the debate over rising air quality index in Delhi is intensifying in the news. But the pollution level on the second day of Diwali this time was already lower than last year. If 2022 is excluded, this morning was the clearest morning on the second day of Diwali since 2015.
According to the Central Pollution Control Board (CPCB) data, the average 24-hour air quality index (AQI) after Diwali on Friday was 339, which was better than the 358 on the second day of Diwali (November 13) in 2023. The worst air quality day after Diwali in 2021, the AQI was 462.
Why is there less pollution this time?
There are many reasons for the low pollution, but one of the most important is the weather at this time. Diwali was celebrated in November last year and the temperature was quite cold at this time. The minimum temperature in November last year was 13 degrees Celsius and the maximum temperature was 27.8 degrees Celsius. This year, Diwali is celebrated at the end of October, when the weather is much warmer than usual. According to IMD, this October was the hottest in the past 73 years.
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The maximum and minimum average temperatures recorded at Delhi’s Safdarjung weather station in October were 35.1 degrees Celsius and 21.2 degrees Celsius respectively. This figure is the fourth highest monthly temperature recorded in Delhi since 1901.
In fact, when temperatures are cooler, a layer of ice forms in the air. Therefore, pollution does not spread in the upper atmosphere but remains in the lower atmosphere.
The wind is also responsible
Another reason for the reduction in pollution is strong winds. Due to strong winds, the pollution spreads better and the polluted air does not stay in one place. Concentrations of small pollutants such as PM2.5 and PM10, which increased in Punjab and Haryana on Thursday due to strong winds burning stubble and setting off firecrackers, fell the next day.
Anumita Roy Chowdhury, executive director of research and advocacy at the Center for Science and Environment, told The Indian Express that this Diwali falls in October and the weather has not cooled down yet. Wind speed after Diwali night is also beneficial in reducing pollution. On Diwali, the air quality remained “poor” till noon and became “very poor” in the evening. Critical AQI levels were observed at many monitoring stations at midnight and continued until 7 am. Nighttime PM2.5 levels have increased significantly since Diwali. It cannot be said how big the contribution of firecrackers is, because there are many other factors involved in this increase.
What was the AQI in different parts of Delhi on November 2?
According to the Central Pollution Control Board’s app Sameer, Delhi’s AQI today, Saturday, was 298. This number is for 6am.
- Alipore 301
- Anand Vihar382
- Ashok Vihar 331
- Bawana 319
- Burari 318
- Chandni Chowk 301
- Dwarka District 8 310
- Punjab Bagh 339
- RK Plum 346
- Rohini 311
- Sonia Vihar328
- Vivek Vihar 322
- Wazirpur 325
