Before flush toilets became the norm in society, every household in Shanghai had a chamber pot - or Matong in Chinese - that residents used to store human waste.

It is estimated that there were about 3 million chamber pots in Shanghai during the peak from the 1950s to 60s.

During this period, most people in the city resided in tiny 10-square-meter units within shikumen (stone-framed gatehouses) style buildings, making it almost impossible to store these chamber pots away from sight. As such, residents resorted to hiding them in special boxes.

Every morning before sunrise, the city's sanitation workers would make their rounds in the neighborhoods, ringing a bell and yelling for residents to take their chamber pots out. The contents of the pots would be emptied into the workers' carts before being whisked away to refuse sites.

This practice of using chamber pots almost disappeared in the early 1980s when flush toilets and public restrooms became commonplace. During this time, people paid just 0.02 yuan to use public toilets.

Today, most residents stay in apartments with modern sanitation systems. Even those still living in shikumen-style buildings have access to flush systems, thanks to the government's continuous efforts over the years to improve the standard of living in such households.