World's 10 Most Polluted Cities Pakistan's Lahore is on top of the list with an average pollution reading of 389.

Stifling smog has made New Delhi 2nd-most polluted city in the world with an average pollution reading of 338.

Cambodia’s capital Phnom Penh is third on the list of the most polluted cities of the world with an average pollution reading of 186.

Pakistan's Karachi ranks as the world's forth-worst city for air quality with an average pollution reading of 176.

Ghana's Accra is fifth on the list of the most polluted cities of the world with an average pollution reading of 174.

Iran's Baghdad is sixth on the list to have the worst air quality with an average pollution reading of 173.

Kolkata, situated in the east, held the seventh position on the list with an Air Quality Index (AQI) of 172.

Kabul, a city of some 6 million, has become one of the most polluted cities in the world — ranking 8th in the list with an average pollution reading of 169.

Bangladesh's Dhanka ranks as the world's ninth-worst city for air quality with an average pollution reading of 168.

China's Chengdu ranks as the world's tenth-worst city for air quality with an average pollution reading of 167.