Question

Why are air pollution levels higher in Mexico City than in other similarly denselypopulated cities?
A.because Mexico City is surrounded by mountains that trap polluted air
B.because Mexico City receives a large amount of precipitation each year
C.because Mexico City contains more cars and buses than other large cities
D.because Mexico City engages in more industrial activity than other largecities

Answer 1

A. Because Mexico City is surrounded by mountains that trap polluted air.

The city lies in a high-altitude basin ringed by mountains, which limits air circulation and fosters thermal inversions that trap pollutants. Intense sunlight at altitude also promotes photochemical smog. Options B–D are not the primary reason (more precipitation would reduce pollution; vehicle and industrial activity contribute but the geographic trapping is the key factor).