With the latest round of global climate change talks set to begin this week in Cancun, Mexico, the assembled delegates should be thankful they're not meeting in, say, Beijing or New Delhi. Those two cities are tied at the top of a list no city should want to be on: those with the world's worst air quality.
SUBSCRIBE AND FOLLOW
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements.Learn more