New Delhi's Diwali-night pollution was far worse than the official morning figures suggested. The Delhi Pollution Control Committee (DPCC) released the previously missing hourly air-quality readings around 8 pm on Monday, and an analysis of that data by Hindustan Times shows PM2.5 — the fine particles that penetrate deep into the lungs — peaked at 3,744 micrograms per cubic metre (µg/m³) at Mundka at 2 am on November 9, more than 60 times India's national 24-hour standard of 60 µg/m³.

Source: Hindustan Times via Daily Jagran

This is a new development in the story this site reported on Monday morning, when Delhi's overall AQI was recorded at 368–376 in the 'very poor' band with several stations in the 'severe' range. The newly released readings cover the hours that had gone blank in the Central Pollution Control Board (CPCB) database as pollution spiked after the firecrackers.

3,744 µg/m³Peak PM2.5 at Mundka, 2 am Nov 9
125Missing station-hours, every one above 1,000 µg/m³
36 of 59Delhi stations blank in CPCB records by 1 am
11DPCC stations that crossed 2,000 µg/m³

According to the analysis, all 125 station-hour readings that were missing from CPCB records and later appeared on the DPCC website were above 1,000 µg/m³ — the cap at which CPCB's central framework stops displaying higher values. Eleven DPCC-operated stations recorded concentrations above 2,000 µg/m³, and by 1 am on November 9, 36 of Delhi's 59 monitoring stations had no PM2.5 readings in the CPCB database at all.

Source: Fact.net.in

An official told Hindustan Times, speaking on condition of anonymity, that technical glitches caused the temporary blackout and that all 43 DPCC stations were operational and recording hourly numbers. The released figures remain provisional: as of 7:58 pm on Monday they had not been integrated into CPCB's records.

Factoring the newly released numbers into CPCB's standard formula would push Delhi's overall AQI for the 24 hours ending 9 am on November 9 to approximately 384, up from the published 370, while the 4 pm bulletin figure would rise from 344 to around 360, the analysis added. The hourly readings are individual measurements, not full-day averages, and are not directly comparable to the 24-hour standard — but they show the scale of the spike Delhi breathed through on Diwali night.

Why it matters

Delhi records some of the world's worst winter air. When peak-hour readings disappear from the public record, the published AQI understates what residents actually breathed — the question now before the boards is why the data vanished at the worst hours, and when the corrected figures will be official.