AQI still 'poor'; 65% pollutants came from outside city in 2025: CREA report, Pg4

Key Highlights:

• Delhi's Air Quality Index (AQI) was in the 'Poor' category at 276 on Saturday, a deterioration from Friday's 236.
• Noida's AQI worsened to 242, while Gurgaon's AQI also declined to 244.
• A CREA report indicated that 65% of Delhi's air pollution in 2025 originated from outside the city.
• Vehicular emissions were identified as the largest local contributor to PM2.5 pollution.
• Stubble burning's contribution to pollution decreased to 4.9% in 2025 from 15.5% in 2024.
• The IMD issued a yellow alert for moderate fog in Delhi.

Detailed Insights:

• Delhi's geographical location makes it vulnerable to polluted air carried by winds, necessitating airshed-level interventions.
• Despite improvements in average PM2.5 and PM10 concentrations in 2025, Delhi did not record a single 'good' air quality day.
• Regional factors and pollution transported into the city outweigh emissions generated within Delhi, especially during winter.
• Local sources contributed 35% to Delhi's pollution, with vehicular emissions accounting for nearly half of the locally generated fine particulate matter.
• Unfavorable meteorological conditions, including calm winds and declining mixing depth, hinder pollutant dispersion.
• The mixing depth is expected to decline from 1,400 meters to around 1,000 meters by January 5 and 6, further worsening air quality.

Key Concepts Involved:

• Air Quality Index (AQI): A metric used to indicate air pollution levels.
• PM2.5: Fine particulate matter with a diameter of 2.5 micrometers or less.
• PM10: Inhalable particles with diameters that are generally 10 micrometers or less.