Delhi residents experienced a relatively better air quality during and after the Diwali festivities this year, a notable outcome attributed to warm weather and strong winds that swept through the national capital. Despite the traditional bursting of firecrackers during the festival, the city’s air quality index (AQI) saw only a minor spike on November 1, the day following Diwali.
Air Quality Index: A Comparative Overview
The 24-hour average air quality measured on Diwali and the day after showed a slight increase compared to previous years. However, it was also the lowest recorded AQI since 2015, except for the exceptionally low figures noted in 2022. According to data from the Central Pollution Control Board (CPCB), the AQI on Friday stood at 339, which was just 11 points above Thursday’s reading of 328. Both readings fell into the ‘very poor’ category.
Compared to previous years, this year’s post-Diwali air quality was a significant improvement. For instance, the AQI recorded the day after Diwali in 2023 was much higher at 358, and 2021 witnessed a concerning peak of 462, marking the worst air quality on record for the festival.
Contributing Factors to Improved Air Quality
Several meteorological factors played a crucial role in maintaining favorable air quality post-Diwali. The warm temperatures experienced this year, coupled with strong winds, contributed significantly to the lower pollution levels.
Last year’s Diwali, celebrated on November 13, coincided with much cooler temperature conditions; the monthly average minimum temperature was noted at 13 degrees Celsius, with a maximum of 27.8 degrees Celsius. In contrast, this year, the festival took place in late October, with temperatures soaring higher than in recent years. The India Meteorological Department (IMD) reported that October 2023 was the warmest in 73 years, with maximum and minimum averages recorded at 35.1 degrees Celsius and 21.2 degrees Celsius, respectively, at the Safdarjung weather station.
Another favorable meteorological condition was the wind speed. Initially low, at about 3 to 7 kmph, wind speeds increased to approximately 15 kmph by noon on November 1. An average wind speed of 10 kmph is typically deemed adequate for dispersing pollutants, aiding in reducing the concentration of harmful particles in the air.
