Seventy years ago, thick polluted smog descended on London bringing the city to a standstill and leading to the deaths of an estimated 4,000 people. Click here to subscribe to our channel 👉🏽 https://bbc.in/3VyyriM The Great Smog of London lasted for four days. In response the government passed the Clean Air Act of 1956 to reduce the use of smoky fuels such as coal. Witness History spoke to Dr Brian Commins, who worked for the Medical Research Council's Air Pollution Unit set up at St. Bartholomew's hospital in London in the 1950s. Hear more 👉🏽 https://www.bbc.co.uk/sounds/play/p0114pw9 Watch more Witness History videos here 👉🏽    • Witness History   ---------------- This is the official BBC World Service YouTube channel. If you like what we do, you can also find us here: Instagram 👉🏽 https://www.instagram.com/bbcworldservice Twitter 👉🏽 https://twitter.com/bbcworldservice Facebook 👉🏽 https://facebook.com/bbcworldservice BBC World Service website 👉🏽 https://www.bbc.co.uk/worldserviceradio Thanks for watching and subscribing! #BBCWorldService #WorldService #london