Stock Photo - Thick smog can be seen over the Red Fort (Lal Qila) in the city of Delhi, India. India's capital, with 18 million residents, has the world's most polluted air with six times the amount of small particulate matter (pm2.5) than what is considered safe, according to the World Health Organization (WHO). The air's hazardous amount of pm2.5 can reach deep into the lungs and enter the blood, causing serious long term health effects. The WHO has declared that India has the world's highest death rate from chronic respiratory diseases. India, home to 13 of the world's top 20 polluted cities, is also the third largest emitter of greenhouse gases behind the United States and China. - DELHI, INDIA, 10/07/2014