Delhi has experienced its cleanest first half of December since the air quality index (AQI) data was first collected in 2015, with significant improvements in air quality across the capital. According to data from the Central Pollution Control Board (CPCB), Delhi recorded an average AQI of 238 from December 1 to December 15, the lowest ever for the month.
For the first time in December since records began, there was only one “very poor” air day and no “severe” air days. In contrast, the city had six “moderate” air days—the highest for December—along with eight “poor” air days. Prior years typically saw an average AQI exceeding 300 in the first half of December. The previous lowest AQI for the same period was 301 in 2022, with the average AQI for last year’s first half of December at 327.
While there has been no “good” or “satisfactory” air days in December since monitoring began, the significant reduction in pollution levels this year stands out. The CPCB defines AQI levels as follows: 0-50 is “good,” 51-100 is “satisfactory,” 101-200 is “moderate,” 201-300 is “poor,” 301-400 is “very poor,” and over 400 is considered “severe.”
Experts attribute the cleaner air to consistent and strong winds across northwest India, coupled with the lack of moisture and fog. “Generally, December experiences moderate to dense fog, which hinders the dispersion of pollutants, but this year, winds have been stronger, averaging over 8-10 km/h, with speeds occasionally reaching 20 km/h,” explained Mahesh Palawat, vice president at Skymet Weather Services. The absence of intense fog and moisture has further helped keep Delhi’s skies clearer.
While the air quality has improved significantly, the conditions are not perfect. Sunil Dahiya, lead analyst at Envirocatalysts, pointed out that Delhi’s background emissions remain high. Even with favorable meteorological conditions, the PM2.5 concentration did not dip below 110 micrograms per cubic meter, which is more than twice the permissible standard of 60 micrograms per cubic meter.
The “very poor” AQI day this month occurred on December 8, with an AQI reading of 302. The CPCB recorded a “poor” AQI on eight days, including Sunday, when the 24-hour average AQI was 294. The forecast from the Centre’s Early Warning System (EWS) predicts that the AQI will likely deteriorate to “very poor” from December 16 to December 18, with air quality fluctuating between “very poor” and “poor” for the following six days.
Despite this, the improvement in Delhi’s air quality during the first half of December marks a notable departure from previous years, offering a glimpse of the positive impact of weather patterns on reducing pollution levels in the capital. However, experts caution that any change in weather conditions could lead to a resurgence in pollution levels.
Sources By Agencies