Tehran emergency services report that 400 people were treated for respiratory and cardiac problems on Monday December 29 as a result of increasing pollution in the capital.

Meanwhile, the Department of Environment announced on Tuesday December 30 that air quality in Tehran had fallen far below the acceptable range and vulnerable groups were urged to refrain from going outdoors.

A number of factories have been shut down and schools have cancelled outdoor gym classes.

The elderly, children and those suffering from heart problems as well as pregnant women were urged to use masks when outdoors or to avoid travelling outdoors if possible.