The Great Smog of London: What Led To It?

by | Nov 25, 2022 | Air Pollution, Environment, Pollution

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The Great Smog of London was a huge ecological disaster that occurred in 1952 due to the high pollution levels in the United Kingdom’s capital. The Great Smog of London affected all the city’s residents but had worse effects on the city’s senior citizens. Over 4,000 Londoners are estimated to have died prematurely.

The severe impacts of the smog on the city pushed policymakers to enact the first air quality legislation in the United Kingdom and laid the foundation for future environmentalism in the country.

How it Began & What Caused It?

On the 5th of December 1952, the residents of London began to suffer from breathing problems after inhaling the thick smog. The Great Smog of London would last up to a whole week and cost 4,000 to 10,000 lives. Smog is a type of air pollution; it is produced by industrial outputs and natural weather patterns.

The disaster began with the settling down of fog on the city on the 5th of December. The fog is a common phenomenon during London’s misty winter weather. The fog eventually turned into smog.

The city of London already had a history of smog, going back to the 13th century, due to the burning of coal. These smogs were called “pea-soupers‘ because of their yellow and brown appearance. Today, they are known as sulfurous smog or “the London Smog”.

As London became more industrialized and modernized, air pollution and smog only worsened. Due to complaints by residents in the 1600s, King James I passed legislation to control pollution. However, it was ineffective.

The situation started getting out of hand with rapid industrialization in the late 1700s. This all reached a critical point in the 1900s with the Industrial Revolution. More and more industries, factories, and domestic hearths led to an increase in emissions. During this period, smogs in London would last for a week, with several deaths reported. However, the Great Smog of London was the worst smog that the city had ever seen.

The Great Smog of London occurred due to the city’s reliance on coal-fired power plants for electricity and heating purposes and diesel-powered buses for public transportation. The weather patterns in London also contributed to the smog.

London is contained in quite a large river valley, limiting air circulation. The night before the Great Smog, a mass of cold air blanketed the whole region, trapping the valley’s warm air below. The trapped warm air had high pollution levels due to London’s factories, homes, and vehicles.

Impacts of the Smog

London Smog, 1952


The smog was so severe that people walking outside on the streets could not even see their feet in certain areas of the city. The government stopped all types of transportation like cars, buses, boats, trains, and flights, except for the London Underground. Because of the smog, several people have to leave their vehicles on the streets.

Due to the lack of visibility in the city, all activities, like soccer games, movie theatres, indoor plays, concerts, etc., were canceled. However, incidents of crime increased rapidly. Burglaries, looting, and wallet snatchings were on the rise as criminals would easily vanish into the smog.

The smog finally lifted on the 9th of December 1952, and the total number of casualties was approximately 4,000. During the Great Smog of London, there was a spike in hospitalizations; several patients were brought in with pneumonia and bronchitis. Smithfield, a district in central London, reported cases of cattle choking to death. The impacts of the smog were long-lasting. Today, experts estimate the total death toll at 12,000.

In the aftermath of the Great Smog, London’s air pollution issue could no longer remain ignored. The Clean Air Act of 1956 was passed four years after the Great Smog to reduce pollution. The government established smoke-free areas across London. Coal burning in domestic hearths and industrial furnaces was restricted, and people were offered grants for shifting to non-coal heat sources like electricity.

Changes took place gradually. After the Great Smog of London, other smog incidents also occurred. For example, the 1962 smog killed around 750 people. However, the Clean Air Act of 1956 still played an important role in the history of air quality legislation.



  • Dr. Emily Greenfield

    Dr. Emily Greenfield is a highly accomplished environmentalist with over 30 years of experience in writing, reviewing, and publishing content on various environmental topics. Hailing from the United States, she has dedicated her career to raising awareness about environmental issues and promoting sustainable practices.

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