Rain does natural cleansing, delivers fresh air to tricity after choking January smog

Mohali saw similar trends, with AQI spiking to 249 on a few days in mid-January, while Panchkula stations reported averages around 204 in peak hours. Primary pollutant PM2.5 levels often exceeded national standards significantly.

The turnaround came with the rains. Meteorological reports confirm light to moderate precipitation across the tricity on February 1, accompanied by thunderstorms in parts of Mohali and Panchkula. This natural cleansing washed away particulate matter through wet deposition, improved wind dispersion and raised the atmospheric mixing height.

By mid-week, many stations reported AQI dropping below 150, offering relief to residents who had endured weeks of hazy skies and health advisories.

Experts attribute January’s poor air quality mainly to winter temperature inversion — a phenomenon where a layer of warm air traps colder air (and pollutants) near the ground.

Foggy conditions, low wind speeds and reduced solar heating exacerbate this, preventing pollutants from dispersing. Sources include vehicular emissions, road dust, construction activities, biomass burning for heating and industrial outputs.

Historically, air pollution in the tricity peaks during the post-monsoon and winter seasons. October-November often sees spikes due to crop residue burning in neighbouring Punjab and Haryana, while December-January brings sustained poor AQI from inversion and calm weather.

Studies on Chandigarh’s air quality trends show PM concentrations are highest in winter, dropping sharply during monsoon due to rain washout — a pattern repeating this February 8.