The 20 million residents of New Delhi, India, are choking through thick smog this week, the New York Times reports—the worst in 17 years. The air is so bad that sustained breathing is equivalent to smoking more than two packs of cigarettes a day, the Times notes.
Schools have been closed for three days, although experts warn that the air inside homes may not be much better than what’s outside. Levels of the most dangerous pollutant, called PM 2.5, have soared, up to a thousand micrograms per cubic meter, or 16 times what the Indian government considers safe. (See more pictures of New Delhi, the world’s most polluted city.)

PM 2.5 is composed of tiny particulates that can lodge in breathing passageways. The average for the city has hovered close to 700 micrograms per cubic meter during this crisis, or about 12 times what the government considers acceptable (that’s actually 70 times worse than the levels recommended as safe by the World Health Organization).
As visibility drops, authorities have blamed car accidents on the pollution. The city’s monuments and views are all but obscured (as is the sun).
Residents have been huddling indoors, next to air purifiers. The young, elderly, and those with respiratory ailments are most at risk of injury, or even death, from the pollution.
On Sunday, Delhi’s chief minister ordered a five-day moratorium on construction and a 10-day closure of a power plant. The government has also advised people to wash their eyes and to seek medical treatment if they experience acute breathing or chest problems. 
Reblogged from National Geographic