Blue and Green: The high levels of pollution have subsided across many parts of the UK, after the most vulnerable were told to stay indoors and avoid heavy exercise for the best part of a week.
Concerns were raised on Tuesday after a combination of events including wind, warming temperatures, dust from a Saharan sandstorm and transport emissions triggered extremely high levels of air pollution. Cleaner air from the Atlantic has forced the smog to subside.
The event led to a 14% rise in 999 calls made to the...