Rain washes away pollutants, 1st week of Sept cleanest in Gurgaon in 6 years
Gurgaon: Every cloud has a silver lining? Bouts of heavy monsoon rain this season flooded streets and brought the city to a standstill but also washed away pollutants from the air.
Data from Gurgaon's only functioning air quality station – Gwalpahari – recorded the cleanest air quality for the first week of Sept in six years. Average AQI dropped to 47.8 – firmly in the ‘good' category.
AQI on Sept 1 was the best, at 39. The week's ‘worst' reading was on Sept 6, when 24-hour air quality index touched a high of 59.
In 2024, average AQI for the city in the first week of Sept – calculated from data from four monitoring stations – was 76 (‘satisfactory'). In 2023, it was 167.7, or ‘moderate'.
2018's average AQI was relatively better, at 44, but data was only recorded for three days over the week. Record-keeping in Gurgaon began only in 2016.
Experts said the reason for cleaner air so far this month was simple – 100mm of rainfall on Sept 1, followed by on and off showers in the days after.
"Rain essentially pressure-washed the city's air. They scrubbed out PM2.5 and PM10 particles, improved visibility and reduced ozone formation by lowering surface temperatures," Shubhansh Tiwari, research associate with the Centre for Science and Environment, said on Sunday.
The week's downpour also reduced vehicular movement and likely affected industrial operations for brief periods due to waterlogging. Gusty winds, too, helped disperse pollutants.
Experts also cautioned against drawing definitive conclusions from limited data. Only one of Gurgaon's four continuous air monitoring stations remains functional, potentially skewing readings compared to the more comprehensive coverage previously available.
With the approaching Oct-Nov period—characterised by stubble burning, festival fireworks, and winter smog — they warned that the improvement may prove fleeting.
"Think of the recent rain as a temporary curtain drawn over a stage where the set is still broken. Once winter sets in, we will be back to the same reality. We must use this intermission to fundamentally change production, instead of presentation, of how we improve NCR's air quality through decisive, coordinated action," Sunil Dahiya, founder and lead analyst at think-tank Envirocatalysts.
An official of the Haryana State Pollution Control Board (HSPCB) acknowledged data limitations of one functional monitoring station, but said efforts were being taken to restore inactive stations.
"Even with limited data, the downward AQI trend is evident. Rainfall played a significant role, but ongoing policy measures are also contributing to gradual improvement," the official said.
