The Clean Air Act was passed in 1956, but it did not come into force until the 1st of June 1858.
The Act introduced a number of measures to diminish air pollution, particularly in the congested cities.
It was brought in after London experienced a catastrophic smog in 1952 during which 4,000 people are said to have lost their lives due to the poor air quality.
The Act restricted what fuels could be burned in urban areas, and also placed regulations on the coal burning electrical plants.