The British Department of Environment, Food and Rural Affairs said Thursday's level of air pollution in London and southeast England hit the maximum level of 10. Forecasters said strong winds from the Atlantic may clear some of the pollution.
"We can’t just rely on a change of weather or wind direction to tackle the deadly air pollution incidents which regularly hit Britain," Friends of the Earth campaigner Jenny Bates said in a statement Thursday. "Strong government action is needed to tackle the underlying problem too."
No part of the country was reported in the maximum range for Friday's forecast.
The European Commission in February said the British government hadn't done enough to reduce the amount of smog-creating compounds from the air.
Friends of the Earth said long-term exposure to particulate air pollutants leads to 29,000 premature deaths each year in the country.