It has shrouded England's most famous monuments for days, prompted a rash of calls to the emergency services over health fears and even stopped Prime Minister David Cameron from taking his early morning jog.
A freak combination of weather conditions has left parts of the country covered in a smog haze made up of high levels of particles, including dust from the Sahara.
Pollution levels in the capital and southeast England were rated at a maximum level of 10 on Thursday, according to the Department for Environment, Food and Rural Affairs (Defra).
In March, air pollution levels in Paris hit such heights that transport chiefs enforced the most drastic traffic curbs in years, making public transport free in the French capital.
Landmarks like London's Big Ben and the huge "Angel of the North" sculpture in the city of Gateshead were shrouded in haze as frustrated tourists try to take pictures through the murk.
The pollution has been a particular bane for those with respiratory problems and health experts have been discouraging people from taking vigorous exercise outdoors.
Asthma UK said an overnight poll showed there had been a surge in reported asthma attacks triggered by the high pollution levels.
Forecasters say the smoggy conditions are likely to last into the weekend.
|