The city sits in a valley surrounded by mountains. Smog from manufacturing and chemical plants as well as vehicle exhaust fumes get trapped by the surrounding mountains due to lack of any powerful-enough winds. This makes up the layer of gloom that sits over the valley due to a "cook-pot effect".
sierra madre mountains
Hills and mountains.
They can lower the mountains so they not so high.
Hills and mountains qualify as such. Both Santiago and Mexico City are surrounded by these, which act as a barrier, preventing strong winds to dissipate the air pollution.
Air pollution qualifies as such. Surrounding mountains and high elevation above sea level contribute to a "cook pot effect", preventing air currents from blowing the smog away, and keeping it trapped in the Mexico City valley below.
It is very difficult to put a blame for Mexico City pollution problems on a specific type of worker or economic class. I would say 'everyone', as the most important issue related to Mexico City is overcrowding.
hazardous air pollution and liter happen in New Mexico.
Amundsen was partially sponsored by Norway, not Mexico.
The name of the mountains that cover much of the northern part of Mexico is Sierra Modre Mountains
It's actually in Arizona, but partially in Northern Mexico.
New Mexico's Mountains
The Rocky Mountains.