In early December 1952, an anticyclone trapped a mass of cold stagnant air over London, creating a weather inversion. However, nature was only half the culprit behind the Great Smog that ultimately claimed up to 12,000 lives. The severity of the disaster was heavily escalated by post-WWII British economic policies.
In an effort to rebuild its post-war economy, the British government prioritized exporting its high-quality, low-sulfur coal overseas to generate foreign currency. To meet domestic heating needs, local power stations and citizens were left with cheap, low-grade 'dirty' coal rich in sulfur. When temperatures plummeted, millions of households burned this low-grade coal simultaneously alongside London's massive coal-fired power plants.
The combustion released vast amounts of sulfur dioxide, which combined with humidity to form highly corrosive sulfuric acid droplets inside the fog. The smog became so thick that transportation ground to a halt, indoor theatrical performances were canceled due to lack of visibility, and thousands succumbed to acute respiratory illnesses within days.