An Air Quality Index (AQI) is a number used by government agencies to measure the air pollution levels and communicate it to the population

As the AQI increases, it means that a large percentage of the population will experience severe adverse health effects

The measurement of the AQI requires an air monitor and an air pollutant concentration over a specified averaging period

The results are grouped into ranges, and each range is assigned a descriptor, a color code and a standardized public health advisory

The pollution sources in India – and in most Asian countries – are numerous and incompletely understood

In Delhi, for example, it comes mostly from light and heavy-duty vehicle traffic emissions, road dust, solid fuel combustion for heating

Cooking, biomass, waste burning, thermal power plants, diesel generators, construction and small-scale local industries

That’s why each country has to have their own AQI values

The air quality index ranges from 0 to 500, though air quality can be indexed beyond 500 when there are higher levels of hazardous air pollution

Good air quality ranges from 0 to 50, while measurements over 300 are considered hazardous