Lucknow: Incessant rain may have caused inconvenience to many, but it cleaned the air across the city.As per Central Pollution Control Board (CPCB) data, Lucknow’s air quality slipped into the ‘good’ category, with the citywide AQI falling to 38 on Saturday — a range commonly associated with clean-air episodes in cities such as Canberra and Sydney (Australia).The improvement was sustained for a third consecutive day. Lucknow’s AQI stood at 48 on Thursday, fell to 37 on Friday and remained at 38 on Saturday, according to CPCB data. Under India’s National Air Quality Index, all three readings fall in the ‘good’ 0-50 category.The effect was even more striking at individual monitoring stations. Central School recorded an AQI of around 25 on Saturday, among the cleanest readings in the city. Gomti Nagar recorded around 36, while B R Ambedkar University and Kukrail Picnic Spot-1 were around 33. Talkatora, however, remained comparatively higher at around 63.For Lucknow, where road dust, traffic emissions and construction activity routinely contribute to particulate pollution, the three-day clean-air spell was an unusual late-monsoon bonus.The prolonged rain acted as a natural atmospheric scrubber, removing suspended particles and suppressing fresh dust from entering the air.“Rain provides a natural cleansing mechanism for the atmosphere. As raindrops fall, they interact with suspended particles such as PM2.5 and PM10 and bring a portion of them down to the surface. When rain continues for several hours, this wet-scavenging process becomes much more effective,” said Alfred Lawrence, a pollution expert at IT College, Lucknow.The rain also tackled one of Lucknow’s persistent pollution sources — road dust.“Once roads and exposed soil become wet, vehicles cannot easily lift and resuspend dust into the atmosphere. This can cause a substantial temporary reduction in particulate matter, particularly PM10. At the same time, changes in wind and atmospheric mixing during the weather system can help disperse pollutants,” Lawrence said.The result was a three-way clean-up: rain removed suspended particles, wet roads stopped dust from being kicked back into the air, and atmospheric movement dispersed the remaining pollutants.
