Pollution index divided into bands
The air pollution index (API) ranges from 0 to 500 and is divided into five bands: 0-25, 26-50, 51-100, 101-200 and 201-500. The bands correspond to low, medium, high, very high and severe pollution.
When pollution is high or severe, not only people with heart or respiratory illnesses will experience aggravation of their conditions but healthy people may notice discomfort.
The roadside APIs are higher than the general API. They are particularly useful for those who spend several hours continuously each day on busy streets.
Bad air quality contributes to many heart and respiratory diseases. A wide range of measures have therefore been introduced to control air pollution.
Control policies have also been stepped up to reduce pol lution from diesel vehicles. Such policies include introducing up-to-date emission standards, tightening inspection requirements and imposing higher penalties on smoky vehicles.
