As December unfolds, Delhi is expected to experience another period of poor air quality, according to data from the Central Pollution Control Board (CPCB). This revelation comes despite the capital managing to avoid entering the “severe” zone in the air quality index (AQI).
CPCB’s analysis of the last five years indicates that Delhi encounters two 15-day intervals with deteriorating air quality – one in the first half of November and another in the second half of December. The latter marks the city’s second most polluted period of the year based on the average AQI.
Experts attribute the hazardous AQI levels observed in November to various factors, including annual farm fires, toxic firecrackers during Diwali, and local emissions. The upcoming December deterioration is primarily linked to local pollutants becoming more pronounced due to low temperatures and dense fog, trapping them closer to the surface.
While December’s air quality has fluctuated between “poor” to “very poor,” forecasts from the Early Warning System (EWS) suggest Delhi might avoid “severe” air quality until December 19. The Delhi Pollution Control Committee highlighted that historically, the first half of November and the second half of December register the highest AQI levels.
Dipankar Saha, former head of CPCB’s air laboratory, explained that low temperatures negatively impact air quality, stabilizing the atmosphere and leading to calm wind conditions. As December progresses with dense fog and limited sunlight, local pollutants trap closer to the surface, resulting in the return of severe air quality days.
While Delhi’s background emissions are notably high in winter, even without stubble burning, the city is urged to remain vigilant. The AQI classifications range from “good” to “severe,” with the recent November averages categorized as “very poor.”
Delhi’s air quality scenario reflects a yearly pattern, with meteorological conditions and emissions playing pivotal roles in sudden pollution spikes. As the city navigates this critical period, attention turns to strategies for mitigating pollution and safeguarding public health.
