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How to read India's AQI

The CPCB Indian Air Quality Index (AQI) converts pollutant measurements into a common index and category. The Indian scale is: Good (0–50), Satisfactory (51–100), Moderate (101–200), Poor (201–300), Very Poor (301–400), and Severe (401–500). These are categories of the Indian index; values calculated using the United States AQI or another country's method cannot be compared as if they were the same scale.

A city AQI in the daily bulletin is a city-level summary over the stated period, not an instantaneous reading at a particular address and not a report of every pollutant. The named main pollutant identifies the pollutant associated with the reported index; it is not by itself a concentration measurement. Check the bulletin date, contributing station count and original source.

Category labels help describe the reported index, but they are not a personal exposure measurement, medical diagnosis, or guarantee about individual health effects. People and locations can experience different exposures. Missing observations mean the source has not supplied a value for that place and period; they do not mean the air is clean.

Pollutants and context

PM2.5 refers to particulate matter no larger than 2.5 micrometres; PM10 refers to particulate matter no larger than 10 micrometres. Sources vary by place and season and can include transport, road and construction dust, industry, power generation, waste burning and fires. Weather affects dispersion, but a single AQI value does not establish a cause or the effect of a particular intervention.

For the official method and source-specific reporting, consult CPCB's National Air Quality Index information and its daily city bulletins. For current Delhi-NCR orders, consult CAQM notices and directions; this page does not report active restrictions.