Coal was the main source of heat and energy in 18th-century England. In 1727, more than 700,000 pounds of coal were delivered to London alone. Residences and factories, tenements and shops, all regularly belched thick clouds of black soot into the city's air.
Much of London was built on top of rank and murky ground. Fleet Street actually started as a marketplace on the covered-over Fleet River, which was known for years by its awful stench. In addition, London cemeteries contained communal graves, or "poors' holes," which were deep enough for seven tiers of coffins, holding three or four coffins in each tier. These pits were left open until they were completely filled with bodies, so the pungent odor of putrefaction wafted about unchecked. Ministers often had to conduct their burial services from a comfortable distance. Churches were also sometimes afflicted by the smell of decaying corpses rising up from their crypts below.
The cinder smoke, mingled with the rank odor of the city's decaying garbage, open sewage, and decomposing corpses, and the stench emanating from the Thames created such a powerful stink that with a proper wind, London could be smelled from several miles away.