
Imagine smog so thick that you can't see your feet as you walk through it; so impenetrable that it blots out the sun; so toxic that it stings your eyes and leaves you gasping for breath.
It may sound like the backdrop to some post-apocalyptic nightmare, but on 5 December 1952, this terrifying scenario became the reality for the people of London. That day’s incident alone killed thousands and prompted a global transformation in the way we deal with air pollution.