The London Marathon, Dedicated To The Olympic Games In 2012

In the second half of the 19th century and the first half of the 20th, London was noted for its dense fogs and smogs. Following the deadly Great Smog of 1952, the Clean Air Act 1956 was passed, leading to the decline of such severe pollution in the capital. In 2010, the City of London was ranked as one of the most polluted places in Europe.
Climate data for London (Greenwich)