Choking smog returned to the skies of Mexico City this week at levels not seen in more than a decade, prompting fears of more eye-watering days to come as efforts to curb pollution run afoul of the courts and the realities of life.
The haze that shrouded the second-largest city in the Western Hemisphere for four days never reached the worst periods in the 1980s and 1990s, but ultimately resulted from the fact that there are still too many cars on the crowded streets.
