Delhi residents have entered their 10th day of hazardous air pollution today (Tuesday, November 5, 2019).
India’s capital city passed the unhealthy milestone a day after authorities introduced a temporary rule to reduce cars on the roads to try to lower pollution levels.
Overall daily Delhi air quality has been hazardous each day since Sunday, October 27. During that time, the air has been coated with a thick brownish haze. City schools have closed. Flights have been cancelled or diverted because of poor visibility. Authorities have enacted a measure to take 4 million cars off the roads by only allowing cars with odd or even license plates on alternate days.
On the worst day – Sunday, Nov. 3 – the average concentration of PM2.5 (fine particulate matter) across the whole city was 509.2 micrograms per cubic meter (µg/m3). This is 568 on the U.S. Air Quality Index and more than 50 times the World Health Organization’s recommended annual guideline.
Delhi’s air quality has been consistently unhealthy since Diwali in late October, when a ban on conventional firecrackers failed to stop pollution levels soaring during India’s biggest annual festival.
The sources of Delhi’s pollution generally include vehicle emissions, industry, construction, power plants and waste-burning.
Current smog levels have been made worse by weather conditions and the actions of farmers in the neighbouring states of Punjab and Haryana. They burn fields to clear the land after crops have been harvested – known as stubble burning – producing smoke that travels across large distances. They will be no immediate let-up in this smoke, as the harvest season lasts until mid-November. Major fires can be seen on the AirVisual air quality and fires map.
Meanwhile, falling temperatures and a lack of rain and winds in Delhi have meant pollutants have stayed around for longer.
Delhi’s previous record was eight consecutive days of hazardous air quality between Nov. 7-14, 2017. The publishing of real-time air quality data in Delhi started in January 2016.
The city average is worked out using the median of all stations reporting timely PM2.5 data across Delhi. During Delhi’s bout of hazardous air pollution, areas of the city have experienced pollution levels more than 150 times the WHO guideline, for example, in Vivek Vihar the U.S. Air Quality Index reached 1604– with a PM2.5 concentration of 1542 µg/m3 – on Sunday, Nov. 3.