Study Reveals: Delhi Ranked as the Sixth Most Polluted City in India in October

National Desk: Delhi has emerged as the sixth most polluted city in India during the month of October, trailing behind neighboring cities Ghaziabad and Noida, according to a new study. The data was revealed in a monthly air quality report released by the Centre for Research on Energy and Clean Air (CREA) on Tuesday.

As per the study, Dharuhera (Haryana) was the most polluted city in October, recording a monthly average PM2.5 concentration of 123 micrograms per cubic meter (µg/m³). The analysis, based on data from Continuous Ambient Air Quality Monitoring Stations (CAAQMS), provided a comprehensive overview of India’s air quality situation.

An official statement from CREA noted:

“Findings show a sharp deterioration in air quality across the country, particularly in the Indo-Gangetic Plains (IGP) and the National Capital Region (NCR).”

Delhi recorded an average PM2.5 concentration of 107 µg/m³ in October — nearly three times higher than September’s average of 36 µg/m³. Despite stubble burning contributing less than six percent to Delhi’s PM2.5 levels during the month, the significant increase highlights the need for long-term mitigation strategies that go beyond short-term seasonal measures like the Graded Response Action Plan (GRAP).

Top 10 Most Polluted Cities in October 2025

1. Dharuhera (Haryana) – 123 µg/m³
2. Rohtak (Haryana)
3. Ghaziabad (Uttar Pradesh)
4. Noida (Uttar Pradesh)
5. Ballabhgarh (Haryana)
6. Delhi (NCR) – 107 µg/m³
7. Bhiwadi (Rajasthan)
8. Greater Noida (Uttar Pradesh)
9. Hapur (Uttar Pradesh)
10. Gurugram (Haryana)

In Dharuhera, PM2.5 levels exceeded the National Ambient Air Quality Standard (NAAQS) on 77% of days, with two days categorized as “severe” and nine days as “very poor.”

Cleanest Cities in October

On the other hand, Shillong (Meghalaya) was India’s cleanest city, with an average PM2.5 concentration of just 10 µg/m³. Among the top 10 cleanest cities, four were from Karnataka, three from Tamil Nadu, and one each from Meghalaya, Sikkim, and Chhattisgarh.

Air Quality Trends Across India

Out of 249 cities, 212 recorded PM2.5 levels below the Indian NAAQS limit of 60 µg/m³, though only six cities met the World Health Organization (WHO)’s safe daily guideline of 15 µg/m³.

• The number of cities with “Good” air quality (0–30 µg/m³) dropped from 179 in September to 68 in October.
• Cities in the “Satisfactory” category (31–60 µg/m³) increased from 52 to 144.
• Those in the “Moderate” category (61–90 µg/m³) rose from 4 to 27.
• Nine cities fell into the “Poor” category (91–120 µg/m³), and one city entered the “Very Poor” category (121–250 µg/m³).

The findings underline a worrying trend of worsening air quality across India, particularly in the NCR region, underscoring the urgent need for sustainable, year-round pollution control measures.