Currently, air pollution is one of the biggest crises facing the world. According to a World Health Organization (WHO) report, in 2010, some 223,000 people around the world died from lung cancer as a result of air pollution. The highest number of death has taken place in China and East Asia.
The Middle East and North Africa is the world's most polluted region, which has a mean level of over 130 mcg (micrograms) per cubic meters. Southeast Asia ranks second in the list.
The World Health Organization has released a report of the world's top 10 polluted cities. Here are the world's 10 worst cities for air pollution.
Lahore, Pakistan
The historic city of Lahore is also one of the most polluted cities of the world. According to a report in 2003, Lahore is the third most polluted city in Pakistan and ranks tenth in the world.
Kanpur, India
Kanpur also has a high rate of air pollution with an average of 209 mcg per cubic meters. It is famous for its leather industries and the emission is very high. It ranks 9th in the list.
Yasuj, Iran
Yasuj is the fourth most contaminated city of Iran and the 8th most polluted city of the world according to the WHO list. Its average level of pollution is 215 mcg per cubic meters.
Gaborone, Botswana
Gaborone is the most polluted city of Botswana and ranks 7th in this list.
Peshawar, Pakistan
Peshawar has been rated to be the second most contaminated city of Pakistan and the 6th most polluted city of the world.
Kermanshah, Iran
On an average, about 5 million people are affected by pollution every day in the developing world. Kermanshah is the most polluted city in Iran and ranks 5th in the WHO list of most polluted cities of the world. The rate is 229 mcg per cubic meters.
Quetta, Pakistan
25 percent of the all deaths in the developing countries are a result of poisoning related to polluted environment. Quetta is the most polluted city of Pakistan and the 4th most polluted city of the world.
This place is jointly shared by Ludhiana, which is also the most polluted city of India according to reports. The pollution was so high that the government issues ban on the industrial pollution in 2010, which was later, lifted in February 2011.
Sanandaj, Iran
At No.3 in the list of most polluted cities is the capital of Kurdish Culture and Kurdistan Province. Sanandaj has an annual mean level of 254 mcg per cubic meters according to 2009 data.
Ulan Bator, Mongolia
Ulan Bator city of Mongolia is at second spot among the world's most polluted cities, with an annual mean figure of 279 mcg per cubic meters. According to a study done by the Public Health Institute of Ulan Bator, the number of people sickened by respiratory disease increased 45 percent between 2004 and 2008.
Ahvaz, Iran
Ahwaz, in southwest Iran produces the country's most oil, is topped the most polluted cities in the world, with an annual mean level of 372 mcg per cubic meters
Particles released by burning petrol and diesel for car and motorcycle combustion, or coal, fuel wood, charcoal and animal waste for heating and cooking kills almost 2 million people every year.
