The Great Smog, a wave of fog thickened by toxic air pollutants which enveloped London and wreaked havoc on its inhabitants, killing thousands, began on December 5, 1952.
Dense fog had begun to materialise during the day and thickened with nightfall, shrouding the capital until visibility dropped to just a few metres. Over the next few days a series of weather-related and atmospheric conditions conspired to worsen the smoke-laden haze to deadly effect.
A particularly cold winter meant that coal fires were burning all over the city, adding their smoke to air already fume-laden by industrial pollutants from the city’s factories.
An anticyclone had settled over the capital, trapping cold, stagnant air under a warm, moist layer above it, meaning that the fog and pollutants were unable to escape into the atmosphere and disperse as they would normally.
Public transport, other than the Underground, was suspended, as were ambulance services, while sporting events were cancelled. As the smog began to seep indoors, some concerts and cinema showings were disrupted. At one point, the smog was so dense that in certain areas people could not even see their feet.
A change in weather meant that the smog finally dispersed on Tuesday, December 9. A government report which followed stated that at least 4,000 people had died as a consequence of respiratory problems it caused, with another 100,000 people affected; more modern research put the death toll at closer to 12,000.