What is causing Mexico City to sink?
https://strangesounds.org/2021/09/water-crisis-mexico-city-video.html
(Has this happened before?)
Why is Mexico City is sinking?
Short answer is because it sits on top of a massive aquifer which provides the city with all of its drinking water but it is being drained faster than it can replenish itself. Thus leaving a massive open area beneath the city that the water would normal provide buoyancy for. Add to that the fact that Mexico City sits on top a very active fault along with an active volcano in the city and it’s a recipe for disaster.
The same reason the central valleys of Ca are, as is Phoenix AZ.
Draw the water out, and the ground settles.