Report · 25 August 2026

180 AQI at Anand Vihar, 24 hours to 4 PM, 25 August 2026, the worst monitor in Delhi today, Moderate on CPCB's documented formula, and PM2.5 set that figure. 13.6 lakh people live within 4 km of it.

103

TODAY, AS MEASURED

Measured on CPCB's documented formula; with the weather removed, the model's 44 stations read 88, against 105 measured.

1.43 crore

NEAR MODERATE OR WORSE

Within 4 km of 22 Moderate-or-worse monitors: 68.2 per cent of Delhi, every pollutant counted.

3.1x

THE WHO 24-HOUR LINE

Delhi's PM2.5 today, as measured, against the WHO 24-hour guideline.

The AQI figures here are calculated with the formula that the Central Pollution Control Board (CPCB) publishes for its air quality index. CPCB's own documents set out that formula: CPCB's note on how the AQI is calculated; CPCB's AQI calculator.

The full report

The complete written report for this day, with every figure and the source it comes from.

Download the daily reportPDF, 4.1 MB

The day in brief

Today, 25 August 2026, 24 hours to 4 PM: worse than last year on the observed index, +20 points; with the weather removed, still 2.3 points worse on the model's count. 2 of 3 pollutants, PM2.5, PM10, show no real improvement. Delhi's AQI was 103, Moderate, calculated with CPCB's documented formula as the mean of 44 stations' AQIs (CPCB's note "How is AQI calculated?" and its AQI Calculator; page 34 sets out the formula). As measured, 42 of the 44 monitors reading PM2.5 were above the WHO 24-hour guideline of 15 µg/m³. 22 of 44 monitors read Moderate or worse on CPCB's documented formula, and 1.43 crore people, 68.2 per cent of Delhi, live within 4 km of one.

The year so far, 1 January to 25 August: the cleaner days of 2026 have been the dirtiest for these dates since 2024, because three days in four read above 111.8 on the particle AQI, against 94.6 on the same dates of 2025. The middle day reads 160.9 against 149.3 on the same dates last year. On an average day, 31.3 per cent of Delhi's reporting monitors, about 13 of 43, sat above 200 on the particle AQI.

The findings

What the report says

The verdict, both rulers

On the weather model's own count of 36 matched stations, the observed year reads +25.5 points; with the weather removed it is still +2.3 points worse, on the model's count across 35 of 36 stations. 2 of 3 pollutants, PM2.5, PM10, show no real improvement. With the weather removed, 35 of the model's 36 matched stations read higher than last year.

Against yesterday: the one-day move

From 115 to 103. On the 43 stations that reported on both days, the 95 per cent interval runs -20.8 to -3 points.

Against last year: the observed reading

Today 103 across 44 stations. The year is judged on the 36 matched stations: 106 today against 86, the mean of the same date ±7 days of 2025 at those stations. The interval runs 10.5 to 29.7 points.

The worst station in the city today

Moderate, set by PM2.5. Its PM2.5 averaged 84.9 µg/m³ over the 24 hours to 4 PM, 5.6 times the WHO 24-hour guideline of 15 µg/m³. Last year this station read 111 on the mean of the same date ±7 days, so the change is +68.9 points. 13.6 lakh people live within 4 km of this monitor. Within 500 m of the monitor, 84% of the land is built up and 14% is under vegetation, so this reading describes a densely built neighbourhood.

The year, from its best days to its worst

On the same 237 complete dates, 1 January to 25 August, the best tenth of days reads 82.9 against 72.8 and the worst tenth 302.2 against 307.8. The days at or below 200 went from 161 to 159.

How much of the city was above AQI 200

That is 13.0 of 43.2 reporting stations, against 29.7 per cent over the same dates last year, a change of +1.6 points on an interval of -4.2 to +7.7, so it is unchanged inside its margin.

Who the monitoring network reaches

Within 4 km live 92 per cent of Delhi's people, within 2 km 45 per cent, and within 500 m only 3.6 per cent. Delhi has 55 monitors in 53 zones, of which 44 reported today, and 30 of the 53 zones stretch past 4 km, the distance that the US EPA's neighbourhood scale treats as the furthest a monitor speaks for.

What each monitor's reading speaks for

That is 68.2 per cent of Delhi, living around the 22 monitors that read Moderate or worse. No monitor read Poor or worse today. Anand Vihar was worst at 180, and 13.6 lakh people live within 4 km of it.

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