What is it like to breathe in one of the most polluted cities on Earth? In November, India’s capital of New Delhi surpassed Beijing as the world’s most polluted city by a factor of ten. And some parts of the capital city saw pollution rise to 40 times the World Health Organization’s recommended safe levels. For the 19 million residents of the city, that’s like smoking 50 cigarettes a day. People have been advised to stay indoors, more then 6,000 schools were closed and some hospitals reported a 30 percent increase in new patients with pollution-related illnesses. Low visibility also prompted United Airlines to suspend fights to and from the city—something airlines rarely do outside of cases of natural disasters.