And the world's most polluted city is ...

By Simon Busch, CNNUpdated 31st January 2014
New Delhi smog can hit 60 times safe levels, India's Center for Science and Environment (CSE) says.
Smoke but no cigar: Beijing has lost its "most dirty" crown.
Smoke but no cigar: Beijing has lost its "most dirty" crown.
ChinaFotoPress/ChinaFotoPress via Getty Images
New Delhi's "killer pollution": deterrent to travelers?
New Delhi's "killer pollution": deterrent to travelers?
Maral Deghati/AFP/GettyImages