Delhi’s Air Quality or Rather Lack of

While it may seem that air pollution in Delhi is a recent concern, the first study pertaining to air quality in Delhi that I am aware of dates back to 1997. Particularly, in this study, the air quality was analysed for a period of 1991 to 1994, during which the Particulate Matter (PM) exceeded WHO’s recommendation for 97% of the days. Twenty years since that study, Particulate Matter still remains one of our main concerns. Back then, rapid urbanisation, growing vehicle ownership and two coal-fired power plants in the city generated most of the dirty air. Today, the concerns albeit not entirely different require a new antidote. Lets answer some of the key questions about Delhi’s air quality or rather lack of.

To understand Delhi’s air quality, lets look at two figures, one above and one below. In the above figure, we have daily AQI for Delhi mapped against time (in months) from 2016 onward. While in the figure below, we have the share of critical pollutants observed in each month through the year. Note, a pollutant is considered critical if it has the highest concentration amongst all the pollutants on a particular day.


Now, instead of starting from January, lets start mid year, from June – peak summer time in Delhi. We have PM as the most frequently observed critical pollutant, largely arising from road dust attributable to construction and vehicular movement. As the rain hits in the month of July and August, the dust settles, so does the pollution. This is the time when Delhi breathes the cleanest. During this period, one can also observe a some reduction in the number of times PM was designated as the most critical pollutant. Subsequently, in the months from September to November, a sharp and consistent rise in pollution can be observed. The slow Eastern/South-Eastern winds bring along the smoke emitted from burning the paddy straw. The farmers in Punjab and Haryana do so in a desperation to clear the land for the next crop before its too late. This brings PM to alarming levels, not just in Delhi, but in a larger northern Indian sub-continent.

Now that we have understood how pollution manifests itself in Delhi differently during summer and winter, the next question that arises is what measures have been taken to clean the air and what else can be done. The first few things that come to my mind is the odd-even road-sharing scheme. First implemented on January 1st 2016 for 15 days, this policy has since then has been implemented twice, once in April of the same year, and then in November, the following year. Soon to be implemented yet again in November this year, the odd-even policy has never succeeded in reducing pollution in its previous three phases as can be seen from the figure below. In fact it is more likely to fail in the winter months given that the source of the pollution being outside Delhi itself, as discussed above.

To counter the pollution crisis, Delhi in fact needs to have two anti-dotes, one to clean up the indigenous air pollution and the other to clean up the exogenous one.

For the latter, a larger co-operation is required among the affected states in India as well as regions of Pakistan. To the farmer who burns the paddy straw, useless to him, incentives and alternatives that can turn waste to wealth coupled with techniques to efficiently do away with the paddy left overs should be provided. One such alternative designed by a team of students at IIT Delhi turns paddy straw to paper. But even more importantly, the farmers must be incentivised to harvest a different crop altogether. India has a huge surplus of paddy, and most of the paddy grown in this region is exported to different countries. Thus it seems very natural that farmers are nudged to harvest an alternate crop.

For the former, a single solution anti-dote would not work. Rather a wide range of solutions are required. These include a push towards cleaner vehicles and infrastructure for the same, as is planned in the Delhi’s Draft EV Policy, which focuses on 2-wheelers and public transit, along with that development of freight parks at the corridor of the city to better manage goods movement can significantly reduce major polluting sources from entering the city.

Has 2019 been better? Yes indeed, 2019 has been better. If we compare the first 8 months of 2019 with previous years, 2019 has had fewer days with AQI above 200. Furthermore, in comparison with 2012, the PM levels have in fact gone down by 25%. It has been suggested that the peripheral expressway that redirects traffic around Delhi rather than through has had a major contribution in this improvement. However, in my opinion it would be very hard to pin down the reason for such an improvement in the air quality unless the pollution inventory for Delhi is updated. With that being said, should we expect the winters to be better than previous years? In my opinion, winters are going to be as bad as they were previously, mainly because the sources contributing to the pollution in winter are completely different from those during the rest of the year, as discussed above.

What can you do this winter? 1. Accept pollution is an issue that affects you. 2. Wear a mask! Last winters when I was in Delhi, I was surprised to see so few people wearing a mask. Rather I felt anxious as I was among the only few wearing a mask. So to start, accept that pollution will affect your health if not in short term then definitely in long term. Get the N95 mask. My friend Sadanand, who himself writes blogs, has elaborated quite well on pollution masks. Wearing a mask wouldn’t just protect yourself but should make others conscious as well. When we collectively do not wear a mask we indicate our lack of concern to the people who are responsible for keeping the air clean. Wearing a mask is not just an act of protecting one self but a symbol of your larger concern for the people around you. With that I end this blog in hope that the days ahead are bright both figuratively and literally.

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