Delhi Air Quality Hits Season's Worst AQI Of 187, Experts Warn Of More Polluted Days

Delhi recorded its worst air quality of the season on Sunday, with the 24-hour average Air Quality Index (AQI) reaching 187, keeping the capital in the upper end of the ‘moderate’ category. At least 16 monitoring stations recorded ‘poor’ air quality, while experts warned that weakening winds and the onset of winter could lead to more polluted days ahead.

The AQI touched 196 at 10 am before settling at 187 at 4 pm, according to Central Pollution Control Board data. Mundka recorded the highest reading among Delhi stations at 273, followed by Narela at 257. The city’s previous higher AQI was 246 on July 13.

Neighbouring parts of the National Capital Region also recorded elevated pollution levels, with Noida reporting an AQI of 281 and Ghaziabad 248.imes

Low Wind Speeds Push Pollution Up

Experts attributed Sunday's deterioration largely to unfavourable meteorological conditions that restricted the dispersion of pollutants.

According to a Times Of India report, Dipankar Saha, former head of the CPCB's air laboratory, said overall emission loads generally remain broadly similar through the year, barring exceptional events such as large fires, crop-residue burning, major construction activity and dust storms. However, wind speed and direction can significantly influence how pollutants disperse.

He said Delhi's air quality worsened as low wind speeds prevented emissions from dispersing effectively.

Delhi typically sees a deterioration in air quality from mid-October as winter meteorology coincides with an increase in farm-fire activity. However, satellite-based fire data may not fully capture changes in the timing of crop-residue burning, Beig said.

The Central Pollution Control Board classifies AQI levels of 0-50 as ‘good’, 51-100 as ‘satisfactory’, 101-200 as ‘moderate’, 201-300 as ‘poor’, 301-400 as ‘very poor’ and 401-500 as ‘severe’.

CAQM Flags Road Dust, C&D Waste Violations

The worsening air quality has also brought renewed focus on local sources of pollution, including road dust and construction waste.

Four flying squad teams constituted by the Commission for Air Quality Management (CAQM) inspected 25 road stretches covering around 35 km of the Inner and Outer Ring Road on October 3. The roads were under the jurisdiction of the Delhi Public Works Department.

The inspection found 17 violations involving high levels of visible road dust and accumulation of construction and demolition waste. CAQM said the findings highlighted the need for stricter implementation of road-cleaning, sweeping and dust-mitigation measures by agencies responsible for the roads.

The deterioration comes after Delhi recorded its lowest September average AQI in five years, according to the Environment Ministry. The city's September 2026 average AQI was 102, compared with 105 in 2025 and 108 in 2023.

With winter conditions gradually setting in, experts expect meteorological factors to become increasingly important in determining how quickly pollutants accumulate over Delhi-NCR.