The EWS forecasts show that the AQI is likely to slip into the "poor" category by Tuesday, the first such instance since June 11, when Delhi last recorded an AQI of 245.

Delhi's air quality has taken a turn for the worse, with forecasts indicating that the city is likely to experience its first spell of "poor" air this season. According to the Centre's Air Quality Early Warning System (EWS), pollution levels are expected to worsen through midweek. On Monday, the air quality deteriorated marginally, with the 24-hour average air quality index (AQI) touching 189 ("moderate") at 4 pm.

AQI levels rises health concerns

The EWS forecasts show that the AQI is likely to slip into the "poor" category by Tuesday, the first such instance since June 11, when Delhi last recorded an AQI of 245.

"Delhi's air quality is very likely to be in the 'poor' category from October 14 till October 16. The outlook for the subsequent six days shows the air quality is likely to be between the 'poor' to 'very poor' category," EWS projections released on Monday said. This is a cause for concern, as poor air quality can have serious health implications, particularly for vulnerable groups such as children, the elderly, and those with respiratory problems.

Current air quality situation

By 4 pm on Monday, three of Delhi's 39 monitoring stations - Anand Vihar (346), North Campus (307), and Okhla (302) - had already slipped into the "very poor" category. Six others, including Mathura Road (276) and Patparganj (300), were in "poor." The Capital has enjoyed 124 straight days of cleaner air - 77 of them "satisfactory" and 47 "moderate" - since June 11, according to CPCB data.

Why Delhi's Air Quality is worsening?

Meteorologists attributed the decline in air quality to calm winds and seasonal transitions that trap pollutants. Mahesh Palawat, vice president at Skymet meteorology, said wind speed has reduced, oscillating between 6-10 km/hr through 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. While stubble burning is not yet the primary cause of the spike in pollution, data from the Decision Support System (DSS) showed that it accounted for 0.62% of Delhi's PM2.5 concentration on Monday.

Transport remained the top contributor to Delhi's PM2.5 at 19.6%, followed by Jhajjar (9.8%) and Sonipat (6.1%). AQI generally starts worsening in October, following the withdrawal of the southwest monsoon and a dip in air temperature. This is coupled with both the start of stubble burning in northwest India and the festival season when firecrackers are burst.

Weather forecast

Forecasts show clear skies will persist in the region, with the maximum temperature likely to touch 34°C by Wednesday. Delhi's minimum temperature stood at 19.0°C - a degree below normal. The minimum is likely to be between 18-20°C on Tuesday and between 19-21°C on Wednesday. With the current air quality situation, residents are advised to take necessary precautions to minimize their exposure to pollution.

Bad News for Delhi-NCR residents: National Capital's clean air days ends, city set for 'poor' AQI as pollution rises