Europeans have a bad habit of defecating everywhere. Hundreds of years ago, an antique collector recorded an event in his book: charles ii took his family and entourage on vacation in Oxford. These gentlemen are graceful and have extraordinary conversation, but they like to urinate everywhere. When they left, they left their urine everywhere in the fireplace, chimney and cellar. The European aristocrats are still like this, and ordinary people can imagine. At that time, Europeans didn't know that feces could be used as fertilizer, so almost all urban residents didn't have special toilets, and they could solve them whenever they wanted.
There is no perfect drainage system. In the Middle Ages, except Rome, almost all cities in Europe did not have perfect drainage systems. Although Rome had it, the drainage system in Rome was blocked later. At that time, the Roman lords were too busy collecting taxes to clear the blocked drainage system. People have to let sewage flow freely along the street. Most cities in Europe are paved with stone slabs, and sewage does not easily penetrate into the soil, so the streets are full of unsightly filth and sludge.
There are no sanitation workers. There was no occupation of "sanitation worker" in medieval European cities, so the garbage in people's lives had nowhere to pile up and had to be thrown into the street. At that time, the government also issued a decree to impose fines on littering in the street, but the punishment was difficult and the legal effect was minimal. 1533, sanitation workers first appeared in Britain. They collect garbage by carriage or boat and transport it outside the city. However, at that time, this job was done by the most humble talents and was dubbed as "the most disgusting job in history".