New Delhi, May 2 -- Mexico City, which is known as the fastest sinking metropolises in the world and home to nearly 22 million people, is sitting on an ancient lake bed and sinking by nearly 10 inches a year. The new satellite imagery released by NASA can now map the ground of the Mexico City and determine how fast the city is sinking.

The U.S.-India satellite NISAR shows where the land has subsided, leading to "fracturing roads, buildings, and water lines" over decades of changes and "extensive groundwater pumping, combined with the weight of urban development, has resulted in the compaction of the ancient lakebed beneath the city for more than a century."

In Mexico City, many downtown streets were once canals, a tradition that continu...