In big cities around the world, from China to Afghanistan, authorities are still fighting the battle against smog. This, despite the fact that 60 years ago, Londoners suffered from a dramatic air pollution event.
These days air pollution in the British capital, London, is less visible than it was in decades past. But, with the high car and truck volume heading along busy inner city streets like Euston Road, experts are still believe that, even if the problem is becoming less visible, it is still causing major problems.
Recently, smog levels in China were linked to the reduced weights of newborn babies in the country. In London, more than 4,000 people still die every year from illnesses linked to air pollution, said a recent House of Commons report.
"There is some evidence that exposure to pollution alone, even if you are a non-smoker, will eventually give rise to lung disease,' says Vice-President of The British Lung Foundation, Keith Prowse.
Prowse says the invisible pollutants contribute to some 9 per cent of all deaths in the British capital and that air pollution costs the Britain's National Health Service substantial amounts of money each year.
'Near busy roads air pollution is twice sometimes three times legal limits or World Health Organisation guidelines in places,' claims Simon Birkett from the Campaign Group Clean Air London.
The so-called Great Smog that hit London 60 years ago in 1952/53 was one of the worst man-made air pollution catastrophes ever. Back then, some 4000 London residents died in a week when the air pollution was at its worst. Another 8000 people died in the weeks afterwards.
Public health information films at the time advised Londoners to get as much clean air at the weekends at possible, and seemed resigned to the fact that smog was the price to pay for a busy and successful industrialised city.
"The Great Smog was a very unusual combination of events,” Simon Birkett told DW. “The weather was very still. It was cold and we had cold air trapped below warmer air. That meant the pollution generated within the city didn't escape."
“Coal burning in homes and pollution from industry was pumping into a thick fog and that created a terrible end result,” Birkett added.
Smog memories last a lifetime
Pamela Hyde was an 11 year old school girl in North West London at the time of the Great Smog.
“You couldn't see anything. You couldn't see the hand in front of your face," she told DW. Hyde remembers having to navigate her way home with friends after the local cinema was closed when the smog seeped in and obscured the screen.
The 71 year old recalls days of disruption due to the smog that winter.
“It was a frightening time," she said. "If you did go out, you were lucky to get back safely as the transport came to a halt. I remember conductors having to stand in front of buses with a torch to guide the driver.”
Great smog changed policy
After initially denying the problem, politicians at the time were eventually forced to take action and the smog did eventually lead to the UK's Clean Air Act of 1956. That law saw coal burning fireplaces in most homes phased out, as well as factories moved to suburbs and away from the cities.
These days, heavy European Union fines can be imposed where targets to cut emissions and particles are not met. In addition, monitoring has improved. There are now a number of air quality stations measuring nitrogen dioxide and sulphur dioxide levels right across London.
Various schemes are in place including low emission zones to limit the number of the worst offenders in certain areas and the UK Government has said it remains committed to meeting EU and other international targets to reduce air pollution in the capital and nationwide.
Still, Keith Prowse says there is nevertheless room for improvement.
"Where air pollution has been reduced it has resulted in a cut in respiratory problems," he told DW. "Still, it's nowhere near the level that people predicted and indicates that we must cut pollution further."
Population growth and climate change - South African rangers try to sell off their rhinos - the Netherlands speeds ahead on cycling - And the World Parks Congress in Sydney.