This is an interesting 9 minute video clip about Mexico City's history and infrastructure challenges.
It reminds me a lot of Lima (Peru) which is also a Megacity with similar water problems where water is delivered by truck to poorer neighborhoods. Considering the sinking soil that Mexico City is built on and that it's next to an active volcano doesn't make it look like a sustainable city at it's current and ever growing size.
At least unlike Venice (Italy) it's not slowly sinking into the ocean but slowly sinking nonetheless. The really fascinating part for me however is that this is not the only similarity with Venice. The original design of the city by the Aztecs with it's canals and floating islands looks amazing.