Delhi has marked its cleanest December since the commencement of air quality index (AQI) monitoring in 2015, with an average AQI of 294, according to data from the Central Pollution Control Board (CPCB). While the average AQI is classified as “poor,” the improvement is significant compared to previous years, with strong winds and record rainfall playing a key role in dispersing pollutants throughout the month.
Despite experiencing six days of “severe” air quality, where the AQI crossed the 400 mark, Delhi’s overall air quality was considerably better than last year. In December 2023, the city’s average AQI stood at 294, a notable drop from 348 in December 2022 and 336 in December 2021. In fact, the second-best AQI recorded in 2015 was 300, while this year’s reading marked the city’s cleanest December.
Experts attribute this improvement to favorable meteorological conditions during the first half of the month. Mahesh Palawat, Vice President at Skymet, explained that strong winds in early December, coupled with limited moisture, allowed pollutants to disperse, thus preventing the usual formation of fog that worsens air quality. The winds helped maintain relatively good air quality until mid-December when a western disturbance led to slower winds and added moisture, causing air quality to deteriorate temporarily.
The second half of December saw a strong western disturbance that brought rain, significantly improving the air quality by settling pollutants and restoring better dispersion with strong surface winds. By the end of December, the city had recorded 53.5mm of rainfall, making it the fifth wettest December since 1901, including a record 41.2mm on December 28, marking the second wettest December day in Delhi’s history.
Despite the positive impact of meteorological conditions, experts caution that the improvement does not reflect long-term progress in controlling pollution. Sunil Dahiya, Lead Analyst at Envirocatalysts, noted that the AQI spikes during unfavorable conditions, such as when it reached 451, indicate that emissions from various sources remain high. He emphasized the need for more decisive action to address local pollution sources.
The month also recorded a significant shift in daily temperatures, with the average minimum temperature at 8.4°C, matching the long-period average (LPA) for December. Daytime temperatures were slightly warmer than usual, with an average maximum of 22.8°C, consistent with the LPA.
While Delhi’s air quality showed a marked improvement in December, experts warn that addressing pollution requires more than just favorable weather conditions. There is an urgent need for continued efforts to reduce emissions and tackle pollution from various sources to ensure long-term improvement in the capital’s air quality.
Sources By Agencies
