In the 18th and 19th century, Britain was abuzz with cranking steam engines, rattling power looms, and clattering machines. Amidst this daily ding, the world was witnessing a defining movement in human history—the Industrial Revolution—that soon spread to the rest of Western Europe. Powered by coal, the production of most things transitioned from hand to machine, spurring a rise in population and air pollution. For the next two centuries, London became infamous for its soot and smog, which turned fatal for about 12,000 people. Now, a new study has shown that this mal air has left its trace in the lofty Himalayan glaciers, thousands of kilometres away from Europe.