World's 10 Most Polluted Cities

6. Kermanshah, Iran:

Kermanshah in Iran ranks sixth on the most polluted cities list. It records for 229 micrograms of polluting particles per cubic meter. Kermanshah is located in western Iran and is well-known for its oil refineries and manufacturing. It was once an agricultural center, but has since then emerged as an industrial center.  It has become one of the chief importing/exporting gates of Iran.

5. Ludhiana, India:

Ludhiana in India shares the fourth position with Quetta in Pakistan. Ludhiana records for 251 micrograms of polluting particles per cubic meter. Ludhiana is the largest city in the state of Punjab, and one of the richest in the whole of India. They produce 50 percent of India's bikes and 60 percent of their tractor parts.