London is really a foggy city.

At the beginning of the 20th century, most people in London used coal as household fuel, which produced a lot of smog. These smog, together with the climate in London, caused the "well-known" smog in London, which is called London fog in English. Therefore, English sometimes calls London "smog", hence the name "Fog Capital". 195212 from February 5 to 9, the fog and haze incident in London caused 4000 deaths. Therefore, the government implemented the Clean Air Act in 1956, prohibiting the use of smog-producing fuels in some parts of London. Today, the air quality in London has improved significantly.

Because the air is humid, rainy and foggy, the city of London is often full of humid fog, so there is another name called "Fog Capital".