When there was an outbreak of cholera in London in the 18th century, leading physicians of the time came up with the idea that sewerage was creating a “deadly miasma” and advised people to move to the country. This of course simply spread the outbreak to the rural areas where it was even more deadly.

The London sewerage system was created to deal with miasma, it wasn’t until late in the 19th century that it was discovered that cholera was spread from contaminated water supplies.