In Mexico City, Tehran, Kolkata, Bangkok, Shanghai, and hundreds of other cities, the air is no longer safe to breathe. In some cities, the air is so polluted that breathing is equivalent to smoking two packs of cigarettes per day.
Lester R. Brown (2008). “Plan B 3.0: Mobilizing to Save Civilization (Substantially Revised)”, p.193, W. W. Norton & Company
