NEW DELHI: Nearly a week after the season’s first monsoon showers brought relief from heat and pollution, Delhi’s air quality remained in the ‘poor’ category for the second consecutive day, with experts attributing the deterioration to dry weather, high humidity, light winds and continued local emissions
According to the Central Pollution Control Board (CPCB), the city’s Air Quality Index (AQI) stood at 246 at 4 pm on Monday, placing it in the ‘poor’ category. Anand Vihar emerged as the most polluted monitoring station, recording an AQI of 380, which falls under the ‘very poor’ category.
Experts said the deterioration highlights that rainfall alone cannot ensure sustained clean air, as meteorological conditions and local pollution sources continue to influence air quality. After the initial spell of monsoon rain, Delhi has remained largely dry, allowing pollutants to accumulate close to the surface.
Mahesh Palawat, Vice President, Skymet Weather, said the widespread rainfall had initially washed pollutants out of the atmosphere. However, the subsequent dry weather, light winds and lingering humidity have prevented pollutants from dispersing efficiently.
He added that dry westerly winds are also carrying loose dust from Rajasthan, while emissions from vehicles and other local sources continue to accumulate, resulting in a rise in pollution levels. According to Palawat, Delhi’s air quality is likely to remain in the current range for the next five to six days unless another spell of rain arrives around July 21 or 22.
Air quality experts, however, cautioned against attributing the decline solely to weather conditions. They said the episode underscores the increasing contribution of local emission sources during the monsoon, a season generally associated with cleaner air.
Palak Balyan, air quality expert and research lead at Climate Trends, said rainfall offers only temporary relief. Once it stops, emissions from traffic, industries and other local sources begin building up again. Unless these emissions are effectively controlled, improvements in air quality do not last, she said.
Balyan added that high humidity causes fine particulate matter to cluster together, while weak winds and limited atmospheric mixing slow its dispersion, leading to a rapid build-up of pollution even after rainfall.
Top five areas with highest AQI
Anand Vihar: 380
Wazirpur: 295
Jahangirpuri: 282
IIT Delhi: 271
Dilshad Garden: 261