Report · 03 September 2026

212 AQI at Aya Nagar, 24 hours to 4 PM, 03 September 2026, the worst monitor in Delhi today, Poor on CPCB's documented formula, and PM10 set that figure. 57,430 people live within 4 km of it.

78.2

TODAY

Delhi's AQI calculated with CPCB's documented formula, the mean of 44 stations.

56.5 lakh

NEAR MODERATE OR WORSE

Within 4 km of 8 Moderate-or-worse monitors: 27.0 per cent of Delhi, every pollutant counted.

1.6x

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, 4.0 MB

The day in brief

Today, 03 September 2026, 24 hours to 4 PM: Delhi's AQI was 78.2, Satisfactory, 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 33 sets out the formula). As measured, 38 of the 42 monitors reading PM2.5 were above the WHO 24-hour guideline of 15 µg/m³. Poor or worse air reached 57,430 people within 4 km of their monitor today, 0.2 per cent of Delhi.

The year so far, 1 January to 3 September: the cleaner days of 2026 have been the dirtiest for these dates since 2019, because three days in four read above 110.1 on the particle AQI, against 89.6 on the same dates of 2025. The middle day reads 156.9 against 146.6 on the same dates last year. On an average day, 30.2 per cent of Delhi's reporting monitors, about 13 of 43, sat above 200 on the particle AQI.

The findings

What the report says

Against yesterday: the one-day move

From 88 to 77. On the 43 stations that reported on both days, the 95 per cent interval runs -18.4 to -2.1 points.

Against last year: the observed reading

Today 78 across 44 stations. The year is judged on the 36 matched stations: 81 today against 81, the mean of the same date ±7 days of 2025 at those stations. The interval runs -9.8 to 11 points, so the honest reading is level, not better.

The worst station in the city today

Poor, set by PM10. Its PM10 averaged 261.4 µg/m³ over the 24 hours to 4 PM, 5.8 times the WHO 24-hour guideline of 45 µg/m³. Last year this station read 58 on the mean of the same date ±7 days, so the change is +154.5 points. 57,430 people live within 4 km of this monitor. Within 500 m of the monitor, 26% of the land is built up and 74% is under vegetation, so this reading describes open ground rather than a residential street, and should not be read as typical of where people live.

The year, from its best days to its worst

On the same 246 complete dates, 1 January to 3 September, the best tenth of days reads 82.8 against 71.9 and the worst tenth 301.4 against 303.8. The days at or below 200 went from 170 to 168.

How much of the city was above AQI 200

That is 12.6 of 43.2 reporting stations, against 28.7 per cent over the same dates last year, a change of +1.6 points on an interval of -4.1 to +7.6, 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 0.2 per cent of Delhi, living around the 1 monitor that read Poor or worse. Aya Nagar was worst at 212, and 57,430 people live within 4 km of it. On the wider count, 56.5 lakh people, 27.0 per cent of Delhi, live within 4 km of a monitor at Moderate or worse.

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