Why did Mexico City sink unevenly in some areas?

Mexico City sinks unevenly primarily because it was built upon the soft, compressible clay sheets of the former Lake Texcoco basin.12

The subsidence is driven by the continuous extraction of groundwater from underground aquifers to meet the city's water demands. As this water is pumped out faster than it can be replenished, the underlying clay layers compress and crack, causing the surface to settle. Because the geological composition of the lake bed varies in density and thickness across the metropolitan area, the ground does not sink at a uniform rate, leading to the uneven settling of the city's infrastructure.13