How to interpret Delhi air quality readings across CPCB and IQAir apps?

checkthis · automated fact-check · How we check · Reel by @peektv_in

The Reel accurately explains why AQI numbers from different apps cannot be compared directly and correctly cites CPCB rules, WHO guidelines, and CAG audit findings. India's CPCB caps its National Air Quality Index at 500 using a 24-hour running average, whereas IQAir uses the US EPA methodology without a 500 cap on hourly data. WHO recommends a 24-hour PM2.5 limit of 15 micrograms per cubic meter, and a CAG audit did flag location issues at 13 Delhi monitoring stations.

6 claims checked
6 sources
Checked 11 Nov 2026
Main source: About National Air Quality Index

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The Reel we checked

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What we checked

India's CPCB National Air Quality Index scale ends at 500.“clarifying that AQI caps at 500”CPCB Defends AQI Methodology Amid Concerns Over Data Reporting Gaps | Asianet Newsable

IQAir uses the US AQI+ system.“IQAir AirVisual platform AQI readings are based on the U.S.”What is the air quality index (AQI)? | IQAir

The World Health Organization recommends a 24-hour average PM2.5 limit of 15 micrograms per cubic meter.“AQG level | 15”Table 3.6, Recommended short-term (24-hour) AQG level and interim targets for PM2.5a - WHO global air quality guidelines - NCBI Bookshelf

Indian CPCB AQI methodology relies on a 24-hour running average.“short-term (upto 24-hours) National Ambient Air Quality Standards are prescribed”About National Air Quality Index

IQAir's US AQI+ system relies on hourly PM concentration averages.“Both CPCB and IQAir follow different methods of calculating air quality index, resulting in different numbers.”Delhi Air Pollution, Air Quality Index Explained: 350 vs 1,100, CPCB vs IQAir, Who Has Got Delhi's AQI Right

In a 2022 audit, the CAG found that all 13 DPCC stations inspected in 2020 were close to trees on multiple sides.“The CAG had flagged issues at 13 CAAQMS sites related to their proximity to trees”Delhi PAC report: Most air quality monitors meet CPCB norms; transport, pollution checks see progress - The Economic Times

What the Reel doesn't tell you

CPCB stated that its 500 AQI cap is a deliberate design feature for the Severe category, and variations across apps reflect different scales and averaging periods rather than errors.
The WHO 2021 Global Air Quality Guidelines specify a 24-hour average PM2.5 limit of 15 micrograms per cubic meter.
A CAG audit report on Delhi vehicular pollution identified site placement issues, such as tree proximity, at 13 DPCC stations.

Short version

✅ TRUE 👉 AQI numbers from different apps cannot be compared directly, while CPCB rules, WHO guidelines, and CAG audit findings are accurately cited. 👉 CPCB caps its index at 500, IQAir uses US EPA methods without a cap, WHO recommends a 15 μg/m³ PM2.5 limit, and CAG noted 13 station issues. 📰 Sources: Asianet News, Iqair 🔎 Full check: send this Reel to @checkthis.chat