About 400 years ago, there was a city in Japan called Edo. Most of its one million people got clean water supplied close to their houses. Human excreta was not dumped into the river. It was used as agricultural fertiliser. The common people had a say in water management, which was based on economy and cost-effectiveness. The rivers were clean....

About 2,300 years ago, there was a city to which all the roads led. The sewers of Rome, however, led to the Tiber river. Its water was unclean. Huge aqueducts