India Air Quality

Hourly pollution and weather for 15 Indian cities since August 2022, loaded daily into BigQuery and modelled with dbt. Every number below comes from the warehouse.

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City-hours modelled
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Complete city-days
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24 IST hours each
City-days PM index "Poor" or worse
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Days where ozone sets the full AQI
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Two indices. The full AQI applies CPCB's National AQI formula to all six modelled pollutants. Modelled ozone sets it on most days, including in coastal cities, so the charts lead with the PM index: the same formula on PM2.5 and PM10 only. Neither is the official CPCB figure, which comes from ground stations; these values are CAMS model output on a grid.

Which cities have the worst air?

Mean daily index, Aug 2022 to today

How often is the air bad?

Share of days in each CPCB category, PM index

Month by month

Monthly mean of the daily index

Compare years with care. The dashed lines mark two upgrades to the CAMS model (27 June 2023 and 12 November 2024), and both changed how dust is modelled. Coarse dust jumps after each one: Delhi's May PM10 averaged 90 µg/m³ in 2023, 173 in 2024 and 366 in 2025. Part of the rise in the pre-monsoon months in the north-west is the model changing, not the air.

Does Diwali show up?

Daily mean PM2.5 (µg/m³), 10 days either side of Diwali

Rain clears the air

Mean PM2.5 by the day's rainfall, all city-days

The daily cycle

Mean concentration by hour of day (IST), µg/m³

The seasons

Mean PM index by calendar month, all years; the stronger the colour, the worse the air