High traffic levels and unusual weather conditions have been blamed for pollution levels in London which could be dangerous to some people.
Londers have been warned not to exercise outside today as pollution levels are recorded as 'very high' - the highest in four years.
Poor air quality is the result of an intense area of high pressure covering western Europe, reports The Mirror.
Vehicle and factory emissions are not being blown away and the government’s forecast predicts pollution levels will hit band 10, the highest level on the scale.
The last time pollution levels hit this mark was in March 2018.
An alert warns: "Adults and children with lung problems, adults with heart problems, and older people, should avoid strenuous physical activity.
"People with asthma may find they need to use their reliever inhaler more often.
"Even healthy people should “reduce physical exertion, particularly outdoors, especially if you experience symptoms such as a cough or sore throat”.
The worst pollution is forecast to be in the city centre, with poor air quality from Stratford in the east to Hammersmith in the west, though pollution levels are expected to be high throughout the entire city.
