It is no secret that Delhi’s air pollution is one of the most talked about in India and across the world. In 2020, Delhi was ranked the most polluted capital city in the world by IQair, an independent monitoring data collection and reporting group. This was despite days of blue skies and clean air inspired by the lockdown.
Delhi has been in the news in the past for some right reasons. In the early 2000s, the city became the first to run its public and para-transit fleets on compressed natural gas, which cut fine particulate emissions by more than 90 percent from their diesel counterparts. In 2015, for the first time, three children filed a public interest litigation in the Supreme Court seeking a ban on the sale of firecrackers ahead of Diwali, creating much-needed public awareness on incidents of high-intensity burning. Delhi also has a 350 km metro rail, the longest in the country, which has, over the past decade, gradually eroded the share of motorized private transport between its satellite cities-Gurugram, Noida, Ghaziabad and Faridabad. Is. All of these actions have one thing in common—each one attempted to remove air pollution at the sources. The message was simple: we need to cut emissions intensity at sources, so that the city and its residents can breathe clean air. And in this fight, every little action helps – whether it is addressing the 3,000 buses plying every day of the year or lighting firecrackers on one day of Diwali or changing the travel behavior of some commuters.
In 2021, as an engineer, I am sad to see that the city is going in the wrong direction to fight air pollution. Delhi Chief Minister Arvind Kejriwal inaugurated an air filtering smog tower in the hope of capturing and burying the city’s air pollution problem. This interference is the equivalent of running a vacuum cleaner in the middle of the road with thousands of vehicles spewing exhaust, mixed with emissions from other fuel combustion activities. There is only one question here: Will the smog tower help clean Delhi’s air? The short answer is no.
From every known science and engineering angle, the concept of vacuuming the air in the open is not a practical solution. In a closed room, with all inlets closed, it makes logical sense to capture a parcel of air, purge it, and expel it from the other end. But, in the open where every gust of wind is soon replaced by another gust of wind, with equal or sometimes more pollution, this attempt to create clean air is an illogical operation.
In addition to the installation cost, public land, electricity and personnel are to be used and the collected dust (if any) is to be dumped on the public grounds, which will eventually be returned to the air. The city does not benefit from the cost of this smog tower. Similar pilots were set up in several Chinese cities, the largest unit being the city of Xi’an, to no avail.
Now just imagine what can be bought for 30 crores – the cost of just one smog tower. It has at least 15 continuous ambient air monitoring stations capable of measuring and relaying air pollution information in real time; At least 10 electric buses with a capacity of 10 trips per day carrying 40-80 passengers per trip; and at least 100 new and efficient garbage trucks capable of safely transporting all residential waste to processing centers. For context, Delhi requires at least 77 continuous air monitors to represent its pollution spatially and temporally and currently operates 38; Delhi needs at least 15,000 buses to meet the demand for public transport and operates less than 5,000; And Delhi needs at least 3 times the current waste management capacity to handle the current load.
Since the 1990s, several studies have been conducted by national and international institutions to determine the causes that pollute Delhi’s air. The answer has been the same in a few different proportions: vehicle exhaust, dust from suspension due to vehicle movement and construction activities, fuel combustion at industrial sources, residential cooking and heating, and open waste burning, all these years. There are activities all over. . Apart from these, there are also seasonal sources like dust storms, post-harvest fires and firecrackers. If the goal is clean air and blue skies, then we need programs with a long-term approach addressing emissions in all of these sources, not band aid solutions like the smog tower aka vacuum cleaner in the middle of the road.
(It appeared in the print edition as “Smoke and Mirrors”)
The author is the founder/director of UrbanEmissions.Info, a repository of air pollution-related information, research and analysis.
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