India's air pollution in five charts
By Gurman Bhatia
8th November, 2016
The air you breathe is not just made of good stuff. There is also dust, dirt, soot and smoke: all of which contains tiny, mostly toxic, particles. This is what scientists call particulate matter or PM. The smallest particles are the worst. They are 2.5 micrometers in diameter, far thinner than a strand of human hair.
In high concentrations, they can be deadly.
PM2.5 levels in Delhi-NCR peaked at 30 times more than the prescribed limit in the week after Diwali.
But Delhites are breathing toxic air throughout the year.
Sensors in most North Indian cities mirror those in Delhi.
Kanpur and Agra witness a spike in early summer when hot winds further pollute the air with dust from construction. The second spike - in October - is because of Diwali and stubble-burning in Punjab and Haryana.
The air is much cleaner in southern India.
Data is sourced from Hindustan Times' Air Quality portal that tracks data from the US Embassy and the Central Pollution Control Board (CPCB) on a real time basis. Daily averages were calculated for each city by combining readings from all stations in the cities from April 1, 2016 to November 6th, 2016. All negative and invalid values for neglected in the calculation. We look at data starting April 2016, because we started collected the data in mid-March 2016.