NEW DELHI – Delhi is poised to record its first significant spell of “poor” air quality this season effectively ending the Capital’s four-month-long streak of “satisfactory” or better air, according to forecasts released by the Centre Air Quality Early Warning System (EWS).
EWS projections indicate that the Air Quality Index (AQI) is likely to slip into the “poor” category by Tuesday October 14, the first such instance since June 11. The outlook for the subsequent six days shows the air quality is likely to fluctuate between the “poor” and “very poor” categories a troubling forecast just ahead of the Diwali festival.
Air Quality Deteriorates Marginally
On Monday, the air quality already showed marginal deterioration. The 24-hour average AQI as released by the Central Pollution Control Board (CPCB) at 4 pm stood at 189 (“moderate”) an increase of 22 points from Sunday’s 167.
By Monday afternoon, three of Delhi’s 39 monitoring stations Anand Vihar (346), North Campus (307), and Okhla (302) had already tipped into the more severe “very poor” category (AQI 301–400), while six others were classified as “poor.”
Seasonal Transition and Calm Winds Blamed
The Capital had enjoyed 124 straight days of cleaner air (77 “satisfactory” and 47 “moderate”) since the last “poor” day on June 11. However, experts state that the familiar smog season has begun, driven by seasonal transitions that trap pollutants.
Meteorologists attributed the immediate decline to calm winds. Mahesh Palawat, vice president at Skymet meteorology, noted that wind speed had reduced, oscillating between 6-10 km/hr on Monday.
“Wind direction is westerly to northwesterly and there will be marginal stubble intrusion. We don’t expect significant change in terms of weather, with similar wind direction and low wind speed to persist,” Palawat said.
Transport Remains Top Pollutant Contributor
The onset of stubble burning, a major factor in previous years, is not yet the primary cause of the spike. Data from the Decision Support System (DSS) showed stubble burning accounted for a minimal 0.62% of Delhi’s PM2.5 concentration on Monday.
Instead, Transport remained the top contributor to Delhi’s PM2.5 at 19.6%, followed by pollution from Jhajjar (9.8%) and Sonipat (6.1%).
The overall worsening of air quality is a result of the southwest monsoon withdrawal, falling temperatures, and low wind speeds, factors which combine with regional stubble burning and festival emissions to severely impact the city’s air every autumn.