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PM2.5 levels stay high despite slight improvement in Delhi’s AQI

Data from AQI.in for the second week of December shows PM2.5 values between 80 and 100 µg/m³ for most of the period and spiking past 150 to 200 µg/m³ on several occasions.

3 min readNew DelhiUpdated: Dec 12, 2025 09:30 PM IST

Doctors have stressed the need for diagnostic screening to detect early signs of respiratory distress. (Source: PTI)

Delhi’s overall Air Quality Index (AQI) eased in the second week of December, but the city’s pollutant profile showed little change in exposure. Between December 7 and 10, AQI moved out of the ‘severe’ level in intervals, but PM2.5 concentrations stayed far above safe limits.

Data from AQI.in for the second week of December shows PM2.5 values between 80 and 100 µg/m³ for most of the period and spiking past 150 to 200 µg/m³ on several occasions. These levels breach the World Health Organization’s 24-hour guideline of 15 µg/m³. PM10 levels remained high too, fluctuating between 180 and 270 µg/m³.

The graph plotted for the second week of December shows Delhi’s AQI. (Source: AQI.in)

Stronger daytime winds brought limited dispersion earlier in the week, allowing composite AQI to soften. Nighttime inversion, low wind speed and high humidity kept fine particles close to the surface.

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On December 12, Delhi recorded 329 AQI, according to the Air Quality Early Warning System (EWS). On December 9, parts of the city saw a layer of haze with the AQI at 294 in the ‘poor’ category, while readings across Delhi-NCR ranged between ‘poor’ and ‘very poor’ at 5.30 am while on December 8, the city reported an average AQI of 318.

Doctors report rise in respiratory stress

Doctors in the city reported more cases of throat irritation, coughing, eye redness and aggravated asthma linked to PM10 exposure. These coarse particles lodge in the upper respiratory tract and inflame nasal passages, which increases vulnerability to infections.

Specialists say that PM2.5 is the more harmful pollutant during this stage of winter. Because of how fine these particles are, it reaches deep into the lungs and enters the bloodstream, triggering inflammation and cardiovascular strain. Long-term exposure links to reduced lung capacity, irregular heart rhythms and higher risk of stroke and heart disease, say experts.

Public-health experts say the gap between AQI levels and pollutants explains why residents experience discomfort even on days categorised as “better” on the AQI scale.

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With stagnant meteorological conditions likely to continue through mid-December, experts advised residents to use a mask while stepping out, limit outdoor exertion and stay updated on AQI levels.