Will Diwali make Delhi's air the worst ever?

A look at the national capital's preparedness to deal with the air pollution this Diwali

On the list of the world’s 20 most polluted cities, a majority are Indian, and the situation might just get worse. Delhi has lately been witnessing cold mornings, and, according to the special Diwali forecast of System of Air Quality and Weather Forecasting and Research (SAFAR), the pollution level in the city during this year’s Diwali could be worse than those during 2014 and 2015. This is attributed to a combination of adverse meteorological factors like slow wind speed and moisture in the air – a major hindrance in the dispersion of suspended pollutants.

SAFAR, part of the Union earth science ministry, had earlier estimated that the average volume (24-hour rolling) of particulate matter PM2.5 and PM10 could be as high as 226 and 425 micrograms per cubic metre, respectively, in the afternoon of October 30.

What does this imply, and how bad could it be for your health? Business Standard takes a look:

What is PM2.5?

The website of the department of health, New York State, defines the term particulate matter 2.5 (PM2.5) as “tiny particles or droplets in the air that are two-and-a-half microns or less in width”. One micron equals about 25,000th of an inch. The width of the larger particles in the PM2.5 size, according to the website, would be about thirty times smaller than that of a human hair.

How does PM2.5 affect your health?

Particles of that size, when mixed with the air you breathe, can travel deeply into your respiratory tract, reaching the lungs. Such an exposure can cause short-term health effects like irritation in eyes, nose, throat and lungs, besides issues like coughing, sneezing and short breath. These can also be detrimental to the health of your lungs and worse if you have conditions like asthma or heart disease. In the long term, exposure to these particles might increase the chances of chronic bronchitis and lowered lung function, even lung cancer and heart disease. Children and the elderly are particularly vulnerable to PM2.5

Where can PM2.5 come from?

These particles can come from multiple sources. Outdoors, they are mostly released by vehicles, exhausts and operations involving combustion of fuels like timber, oil or coal. Fine particles are also formed by reaction of gases in the atmosphere, especially those released by power plants. The chemical reactions that form these need not necessarily occur at the source of release; they can happen miles away. 

Indoors, PM2.5 can come from tobacco smoke, cooking activities, burning of lamps or candles, etc.

How bad is the situation in Delhi?

The Delhi government recently released a NASA image dated October 26 to show a haze blanket across north India because of burning of crop residue in Haryana and Punjab. This was having a major adverse effect on Delhi’s air quality, news agency PTI quoted the city government as saying.

What steps is the Delhi government taking?

Delhi government announced a three-tier air treatment system that includes setting up of wind purification units, mist fountains and virtual chimneys at five major traffic intersections, on a trial basis, to deal with the rising air pollution in the city.

Purifiers are reported to have been installed at the traffic intersections of Anand Vihar, ITO, Sarai Kale Khan, Kashmere Gate and IIT (Delhi) or AIIMS.