Q: Do China’s cities have the world’s worst air pollution?

A: No.

Q: Umh, what about all those articles about the subject?

A. Most of the articles regarding China’s air pollution problem (and there certainly is one), don’t offer any data. That is, they merely state that the air in China’s cities is the worst.

Or, if they do provide data, it usually isn’t comparative in nature. For example, they’ll give the air quality index for a city in China, tell you it is bad (which it probably is), but then won’t tell you how cities in other countries are faring.

Q. Okay, fine, which countries have worse urban air pollution?

A. For those countries for which there is data, they are:

No	Country	Data
1	Mongolia	279
2	Botswana	216
3	Pakistan	198
4	Senegal	145
5	Saudi Arabia	143
6	Egypt	138
7	United Arab Emirates	132
8	Iran (Islamic Republic of)	124
9	Nigeria	124
10	Kuwait	123
11	Bangladesh	120
12	Bosnia and Herzegovina	117
13	India	109
14	Nepal	106
15	Ghana	98

Q. Where is this data from?

A. The World Health Organization.

In particular, a page on Public Health and Environment (PHE): outdoor air pollution, charting exposure to particulate matter less than 10 µm in diameter in urban areas*, from data available between 2003 and 2010.

Q. Can I look at the data myself?

A. Sure.  The data is available (in sortable table, bar chart, and map forms) at:

http://gamapserver.who.int/gho/interactive_charts/phe/oap_exposure/atlas.html

Note: See underneath the map for information regarding the asterisk in the previous answer.