How bad is the sinking? Sewage tunnels are running backwards as the city sinks up to 8 inches a year. One sewage canal backed up, broke through a dike, then flooded 4,000 homes with raw sewage. Yuck.
The Aztecs had the same problem. But millions of residents and a dropping water table have exacerbated the problem.
“A water pipe installed at ground level in 1934 now juts 27 feet in the air beside the Monument to the Revolution.”
Parts of the Central Valley in California have the same problem,due to groundwater pumping. But that area is mostly farmland. See the photo!.