The Great Smog of 1952

On the morning of Friday 5th December 1952, the city of London began to disappear. A thick, yellow-grey fog settled over the streets, and by lunchtime it was difficult to see further than a few steps in any direction. Buses crawled. Taxi drivers walked in front of their own vehicles, holding torches, to guide their passengers home. By the end of the day, the city was almost completely blind.

The fog itself was not unusual — London had been famous for its "pea-soupers" since the time of Charles Dickens. What was unusual was the cause. A blanket of cold air had settled over the city, trapping every chimney's smoke beneath it: smoke from coal fires in homes, smoke from factories, smoke from steam trains, and even smoke from the buses themselves. The pollution had nowhere to go.

For four long days, the city stopped working. Concerts were cancelled because audiences could not see the stage. Cattle at Smithfield Market suffocated in their pens. Children walked to school holding the hand of the child in front so that nobody got lost. Inside houses, the fog seeped under doors and through letter-boxes, leaving a thin yellow film on every windowsill.

When the fog finally lifted, on the morning of Tuesday 9th December, the true cost became clear. In the weeks that followed, more than 4,000 Londoners died from the effects of the smog. Later studies suggested the real figure was closer to 12,000.

The Great Smog forced Parliament to act. Four years later, in 1956, the Clean Air Act became one of the first laws in the world to control air pollution from homes and factories. Today, when British cities track air quality on a phone app, they are doing it because of the four lost days in December 1952.