Bengaluru welcomes winter early; decline in air quality expected

Bengaluru residents have been bundling up earlier than usual this year, as temperatures in the city dip unexpectedly ahead of the typical winter season. Minimum temperatures over the past few days touched 16°C, marking an unusually early onset of winter, typically expected in December. La Niña, characterized by cooler-than-normal Pacific Ocean surface temperatures, is playing a key role in this early chill, according to meteorologists.

However, Bengalureans are having to carry their masks along with sweaters when they leave their homes. The colder weather is bringing more than a nip in the air — it’s impacting Bengaluru’s air quality. The city’s Air Quality Index (AQI) on November 25 was recorded at 116.

As of today, areas such as Hebbal, Jayanagar and Silk Board have recorded air quality indexes over 100, according to the CPCB. While this moderate AQI is not nearly as damaging as the kind of air pollution in Delhi-NCR, it could still spell trouble for certain groups, such as children and individuals with respiratory issues.

Why winters worsen the AQI

The winter weather exacerbates the problem of air pollution due to a phenomenon known as thermal inversion. In colder months, a layer of warm air traps cooler air below, preventing the dispersion of pollutants from vehicles, industries, and construction activities. With high humidity and low wind speeds further stalling pollutant dispersal, particulate matter (PM2.5) levels rise, worsening respiratory health risks and reducing visibility.

Adding to the woes are Bengaluru's ongoing challenges with vehicular emissions, construction dust, and industrial pollution, which remain major contributors to deteriorating air quality. While residents are advised to check AQI levels regularly and take precautions such as wearing masks or using air purifiers, there’s hope on the horizon. The city is expected to receive rainfall on November 26 and 27, which could help improve air quality by washing away pollutants.

As Bengaluru adjusts to an unusually cold and challenging start to winter, these shifts highlight the need for sustainable urban planning and stricter emissions controls to balance its climatic allure with its air quality concerns.