The Indian government has temporarily shut down all schools in the country's capital on Sunday after Delhi's Centre for Science and the Environment declared an "emergency situation" following six days of pollution that was so bad that the air quality index ran out of numbers to measure it.
Delhi's schools will be closed for three days while officials try to get the pollution levels under control by halting construction and demolition work until Friday, temporarily shutting down a coal power station, fighting fires at landfills, and spraying water on the streets to suppress dust.
The concern is over PM 2.5, micro particles that can travel deep into the lungs and lead to severe respiratory and heart issues. On Monday, PM 2.5 levels were so high that Delhi's air quality index reached 999, meaning that it literally ran out of numbers to quantify how bad the air was.
A 999 air quality index value is approximately 16 times over the safe limit of 60 that is set by India's pollution control officials and 90 times the safe level set by the World Health Organization. For the sake of comparison, Los Angeles is the most polluted city in the United States and only has a mean Air Quality Index value of around 65.
Although Delhi's pollution levels invariably rise during the winter months, this last week was particularly bad because of Diwali, an annual festival that involves lighting fireworks in the city for two straight days. There are so many fireworks being lit during Diwali that the smoke becomes an environmental concern that compounds the already poor air quality in the city. The air quality index hit 999 for the first time this week the day after Diwali, although the sustained pollution levels are the result of massive crop burns being conducted by farmers to the north of Delhi in the Indian state of Punjab.
The move to shut down schools aims at keeping Delhi's kids from having to travel through the toxic environment, something which Tehran and Beijing both did last year for the first time ever. Closing schools to prevent children's exposure to pollution had also been floated last year in Delhi, but never enacted.
Shuttering Delhi's schools was a measure taken with the best intentions, but unfortunately is unlikely to do much good. A 2015 study found that nearly half of Delhi's 4 million children had deficient lung function that would never improve.
Still the Indian city is desperately trying to figure out ways to shed its title of the most polluted city in the world, which range from an app to snitch on polluters to an odd-even scheme that limits the number of cars on the road on a given day.
Correction: This article has been updated to note that the sustained pollution levels are the result of massive crop burns being conducted by farmers to the north of Delhi in the Indian state of Punjab.