With over 20 million residents, can Mexico City avert disaster and become water sustainable?

Can a mega-city mobilize its 22 million citizens to become water sustainable? Mexico City was built not near water but in the middle of a lake. To supply it with fresh water is such a task that it makes it compulsory to bring it from other states. In addition once sewage water leaves the city it end up in agriculture. This film is an environmental case study of the Valley of Mexico as it struggles to save itself while its population grows.