Data from the government's Central Pollution Control Board (CPCB) showed the air quality index, which measures the concentration of poisonous particulate matter, was an average of 449 on Monday. This is the worst level since anything above 100 is considered unhealthy. India's toxic air claimed 1.24 million lives in 2017, or 12.5% of total deaths, according to a study published in Lancet Planetary Health this month.
