Why is London called the foggy city?

Before the 1960s, most people in Dunham used coal as household fuel, which caused a lot of smog and chaos. Although the street lamp is on, the visibility is still poor, and you can't see anything beyond 10 meter clearly. I always feel that my eyes are blurred in front of people. Since then, London has been called the foggy city.

Extended data:

Influenced by the North Atlantic warm current and the west wind, London has a temperate maritime climate, with small temperature difference between the four seasons, cool summer, warm winter, humid air and rainy fog, especially in autumn and winter.

The temperature in London in summer is around18 C, sometimes reaching 30°C or even higher. The temperature is maintained at around15 C in spring and autumn, and fluctuates around 6 C in winter. There is little ice in London in winter.

Thames is an important river in London. It originated in the Cotswolds near Ceste in Salem, southern England. It flows from west to east, turns southeast at Oxford, turns northeast at Reading, turns east again at Windsor, flows through London, and finally flows into the North Sea near Southend.

References:

Baidu Encyclopedia-London