In late October 2024, Delhi experienced a notable fluctuation in air quality surrounding the Diwali festival. The 24-hour average Air Quality Index (AQI) recorded post-Diwali was 339, a marked improvement from previous years, especially the peak of 462 in 2021. This year’s celebration coincided with warmer temperatures, which influenced pollution levels.
About Air Quality Metrics
The Air Quality Index (AQI) serves as important indicator of air pollution levels, ranging from good to hazardous. In Delhi, common pollutants include particulate matter (PM2.5 and PM10), nitrogen dioxide, and sulphur dioxide. PM2.5, which can penetrate deep into the lungs, is particularly concerning during festive periods when the use of firecrackers escalates.
Meteorological Influences
The October 2024 temperatures were recorded as the warmest in 73 years, with averages reaching 35.1 degrees Celsius. Warmer temperatures can hinder the dispersion of pollutants, as cooler air typically allows for a higher inversion layer, trapping pollutants closer to the ground. This inversion phenomenon is crucial in understanding why air quality can deteriorate during colder months.
Role of Wind Patterns
Wind plays a very important role in dispersing air pollutants. During Diwali 2024, favourable wind conditions were observed, with speeds increasing from 3-7 km/h to 15 km/h throughout the day. Such winds help dilute concentrated pollutants, leading to a reduction in the AQI following the festival. The Centre for Science and Environment noted that these wind patterns were instrumental in clearing the air post-Diwali.
Comparative Analysis of Past Years
The air quality during Diwali has shown a trend of deterioration over the past few years, with 2021 marking a peak in pollution levels. The drop in AQI in 2024 can be attributed to the combination of warmer weather and effective wind patterns, contrasting sharply with the colder conditions of previous years that exacerbated pollution.
Impact of Firecrackers and Stubble Burning
Firecracker usage during Diwali contributes to air pollution. In addition, stubble burning in neighbouring states like Punjab and Haryana adds to the problem, especially when atmospheric conditions are unfavourable. While the exact contribution of firecrackers to the pollution spike during Diwali is challenging to quantify, it remains a critical factor in the overall air quality degradation.
Questions for UPSC:
- Discuss the impact of meteorological conditions on air quality during festive seasons in India.
- Analyse the role of wind patterns in mitigating air pollution in urban areas.
- Evaluate the effectiveness of current policies aimed at controlling air pollution during festivals.
- What are the health implications of PM2.5 and PM10 pollutants?
- Compare the air quality trends in Delhi during Diwali over the past five years.
