The principal problems now facing Mexico City are its overcrowding and overpopulation, its dangerous environment, its dwindling water supply, and its terrible air pollution.
	One of Mexico City's problems is that it has an enormous population that continues to rapidly increase every day.  There are many people that move to Mexico City and many people that are born there every year.  These factors contribute even more to its overcrowding and overpopulation.  Another problem is Mexico City's habitat.  It is located in the Valley of Mexico, which is highly vulnerable to volcanic eruptions and earthquakes.  These natural disasters cause much destruction to Mexico City.  Yet still another problem with Mexico City's habitat is the overall instability that is caused by the fact that much of the city is located on a weak, dry-lakebed surface.
	Mexico City's rapidly diminishing water supply creates another dangerous problem.  Once its water supply is gone, the only way to receive water will be to transport it from across the mountains.  Not only does the city have to pipe water in, but it also has to pipe the sewage out of waste-filled areas.  This would be a very expensive undertaking and could cost Mexico City a large amount of money.  Mexico City's worsening air pollution is the most dangerous problem and health hazard presently facing the city.  The air in the city is so polluted that at times the air quality exceeds 100 times the acceptable level.  Thousands of factories and millions of vehicles are the main causes of the air pollution in Mexico City.  Mexico City has many problems at the present time, and it does not look as if it is going to get much better in the future.