The Great Stink
The Great Stink was a time in the summer of 1858 during which the smell of untreated human waste was very strong in central London. At the time house waste was permitted to be carried to the Thames via the sewers, so human waste was dumped into the Thames and then potentially pumped back to the same households for drinking, cooking and bathing.
Furthermore, there were over 200,000 cesspits in London. Emptying one cesspit cost a shilling - a cost the average Londoner could ill afford - thus, most cesspits added to the airborne stench. The introduction of flush toilets also contributed to the problem as they dramatically increased the volume of water and waste that was poured into the cesspits. These often overflowed into street drains designed originally to cope with rainwater, but now also used to carry outfalls from factories, slaughterhouses and other activities, contaminating the city before emptying into the River Thames.
The summer of 1858 was unusually hot. The Thames and many of its urban tributaries were overflowing with sewage; the warm weather encouraged bacteria to thrive and the resulting smell was so overwhelming that it affected the work of the House of Commons (countermeasures included draping curtains soaked in chloride of lime, while members considered relocating upstream to Hampton Court) and the law courts (plans were made to evacuate to Oxford and St Albans).
Heavy rain finally ended the heat and humidity of summer and the immediate crisis ended. However, a House of Commons select committee was appointed to report on the Stink and recommend how to end the problem.