Via The Guardian: Toxic smog covers Delhi after Diwali. Excerpt:
Delhi has been blanketed in a toxic fog the morning after the Hindu festival of Diwali, when hundreds of thousands of people in the Indian capital celebrate by setting off crackers and fireworks.
Air quality in the Indian capital, one of the world’s most polluted cities, is usually very poor due to road dust, open fires, vehicle exhaust fumes, industrial emissions and the burning of crop residues in neighbouring states.
But the density of some harmful particles and droplets in the air spikes for days after Diwali and can reach up to 42 times the safe limit.
An air quality station at the US embassy in Chanakyapuri, one of the city’s greener districts, recorded a PM2.5 level of 999 on Monday morning. India’s pollution control board sets the safe limit for PM2.5 – which measures particulate matter smaller than 2.5 micrometres – at 60.
By contrast, the highest PM2.5 level recorded in London on Monday morning was 139, at a measuring station in Farringdon. Averages tend to be far lower across the year, at about 16, according to a 2010 study.
PM2.5 particles and droplets are considered to be the most harmful kind of air pollution because they are fine enough to evade the body’s natural filters, penetrate the lungs and enter the bloodstream.
Short-term exposure can trigger coughing and eye and throat irritation, while longer term exposure is strongly associated with reduced lung function, heart disease and lung cancer.
A 2015 study found about half of Delhi’s 4.4 million schoolchildren had compromised lung capacity and would never completely recover.
The latest count at the US Embassy, according to the Delhi Air Quality Index, is 175. But counts in other areas of the city are as high as 461 and 347.
