Map of Mexico City
Here is a map of the Valley of Mexico, where Mexico City is situated. As you can see, Mexico City is surrounded by mountains in the south, east and west, which is very unfortunate because the mountains make it very difficult for the wind to vent the city. Hence, all the emissions from cars and industries are trapped within the valley and air pollution can reach very high levels.
Towards the south, on the other side of the mountains, is Cuernavaca, where I live.
Air Pollution Sources