Report · 02 October 2026

246 AQI at IIT Delhi, 24 hours to 4 PM, 02 October 2026, the worst monitor in Delhi today, Poor on CPCB's documented formula, and PM10 set that figure. 6.9 lakh people live within 4 km of it.

173.9

TODAY

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

1.82 crore

NEAR MODERATE OR WORSE

Within 4 km of 43 Moderate-or-worse monitors: 86.9 per cent of Delhi, every pollutant counted.

4.1x

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, 3.9 MB

The day in brief

Today, 02 October 2026, 24 hours to 4 PM: Delhi's air today is 61.6 points worse than on this date last year, which is 53.5 per cent higher, and 7.6 points worse than yesterday, on the Central Pollution Control Board's own readings. Delhi's AQI was 173.9, 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 32 sets out the formula). Above AQI 200 today: 8 stations, IIT Delhi 246, IHBAS 244, Bawana 235, Jahangirpuri 234, and 4 more in the station table. Poor or worse air reached 76.2 lakh people within 4 km of their monitor today, 36.4 per cent of Delhi.

The year so far, 1 January to 2 October: the cleaner days of 2026 have been the dirtiest for these dates since 2019, because three days in four read above 106.1 on the particle AQI, against 90.7 on the same dates of 2025. The middle day reads 149.3 against 134.9 on the same dates last year. On an average day, 27.3 per cent of Delhi's reporting monitors, about 11 of 43, sat above 200 on the particle AQI.

The findings

What the report says

Against yesterday: the one-day move

From 166 to 173. On the 43 stations that reported on both days, the 95 per cent interval runs 3.6 to 11.5 points.

Against last year: the observed reading

Today 174 across 44 stations. The year is judged on the 37 matched stations: 177 today against 115, the mean of the same date ±7 days of 2025 at those stations. The interval runs 51.9 to 71.6 points.

The worst station in the city today

Poor, set by PM10. Its PM10 averaged 294.4 µg/m³ over the 24 hours to 4 PM, 6.5 times the WHO 24-hour guideline of 45 µg/m³. 6.9 lakh people live within 4 km of this monitor. Within 500 m of the monitor, 40% of the land is built up and 60% is under vegetation, so this reading describes a mixed neighbourhood.

The year, from its best days to its worst

On the same 275 complete dates, 1 January to 2 October, the best tenth of days reads 74.2 against 72.0 and the worst tenth 291.3 against 292.8. The days at or below 200 went from 199 to 197.

How much of the city was above AQI 200

That is 11.4 of 43.2 reporting stations, against 25.9 per cent over the same dates last year, a change of +1.5 points on an interval of -3.5 to +6.7, 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 36.4 per cent of Delhi, living around the 8 monitors that read Poor or worse. IIT Delhi was worst at 246, and 6.9 lakh people live within 4 km of it. On the wider count, 1.82 crore people, 86.9 per cent of Delhi, live within 4 km of a monitor at Moderate or worse.

Back to the daily archive