New Delhi | October 14, 2025:
After enjoying over four months of relatively clean air, Delhi’s air quality has once again dipped into the “poor” category, marking the end of the city’s longest moderate air spell since June. The national capital recorded an Air Quality Index (AQI) of 201 on Tuesday morning, as per the Central Pollution Control Board (CPCB) — its first “poor” reading since June 11, when the AQI had reached 245.
End of a 124-Day Clean Air Run
According to CPCB data, Delhi enjoyed 124 consecutive days of improved air quality since mid-June — including 77 days classified as “satisfactory” and 47 as “moderate.”
However, that streak has now been broken with the onset of post-monsoon weather changes, lower wind speeds, and the gradual return of pollution sources that typically worsen air conditions ahead of Diwali.
On Monday, Delhi recorded a “moderate” AQI of 169 at 9 a.m., which rose to 189 by 4 p.m. — a 22-point increase from Sunday’s AQI of 167.
EWS Predicts ‘Poor’ to ‘Very Poor’ Air Days Ahead
The Centre’s Air Quality Early Warning System (EWS) has projected further deterioration in the coming days.
“Delhi’s air quality is very likely to remain in the ‘poor’ category from October 14 to October 16. The outlook for the subsequent six days indicates it may oscillate between ‘poor’ and ‘very poor’,” said the EWS bulletin released on Monday.
Meteorologists attribute the decline to slowing wind speeds, dry conditions, and increased particulate accumulation, conditions typical during the pre-winter period in Delhi.
Meteorologists: Low Wind Speed, Slight Stubble Intrusion
Mahesh Palawat, Vice President (Meteorology and Climate Change) at Skymet Weather, said that the current weather pattern is not conducive for pollution dispersion.
“Wind speed has dropped to 6–10 km/h, and the direction remains westerly to northwesterly. There will be marginal stubble intrusion, but we do not expect any major change in weather patterns this week,” Palawat told Hindustan Times.
He added that stable atmospheric conditions and reduced vertical mixing have started trapping pollutants close to the ground — a precursor to Delhi’s annual smog season.
Stubble Burning Yet to Play Major Role
Despite seasonal expectations, stubble burning is not yet a major contributor to the pollution spike. Data from the Decision Support System (DSS) — a model that estimates the source-wise contribution to Delhi’s PM2.5 concentration — showed that farm fires accounted for just 0.62% of Delhi’s PM2.5 levels on Monday, up slightly from 0.24% the previous day.
Experts said the real impact of stubble burning typically becomes visible towards late October and early November, when large-scale residue burning in Punjab and Haryana coincides with stagnant weather conditions in the NCR region.
CPCB Classification of Air Quality
According to CPCB standards, air quality is classified as:
- Good: 0–50
- Satisfactory: 51–100
- Moderate: 101–200
- Poor: 201–300
- Very Poor: 301–400
- Severe: 401–500
An AQI between 201–300 indicates increased breathing discomfort, especially among children, the elderly, and those with respiratory conditions such as asthma and COPD.
Delhi Govt’s Green Push: Southern Ridge to Become ‘Reserved Forest’
Amid the worsening air, the Delhi government on Monday announced plans to declare the 41-kilometre stretch of the Southern Ridge as a “Reserved Forest.”
Chief Minister Rekha Gupta said the decision aims to strengthen the city’s green cover and protect it from encroachment and environmental degradation.
Taking to X (formerly Twitter), she wrote:
“The Delhi government has taken a crucial step in protecting the capital city from pollution and strengthening its environmental balance. Declaring the Southern Ridge as a Reserved Forest will play a major role in improving Delhi’s air quality.”
Environmental experts have welcomed the move, noting that the Ridge acts as Delhi’s green lung, absorbing carbon dioxide and filtering particulate matter. However, they cautioned that long-term air quality improvement will depend on sustained emission control, waste management, and mobility planning during the winter months.
Smog Season Returns
With the monsoon retreat, dropping temperatures, and festive emissions expected to rise in the coming weeks, Delhi is entering what experts call its “smog season” — a period that typically lasts from mid-October to January.
Pollution levels are likely to spike further around Diwali, when firecracker emissions combine with stagnant weather and farm fire smoke, pushing air quality into the “very poor” or even “severe” range.
Authorities have urged residents to avoid outdoor physical activities during morning and evening hours and to use air purifiers indoors if possible.
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