Indian Clean Air Advocates Slam Supreme Court Order Pushing Questionable “Smog Tower” Technology
Existing smog tower stands in the Lajpat Nagar neighborhood of south-east Delhi.

Environmentalists and scientists have called out the recent Indian Supreme Court decision directing the government to install “smog towers” in Delhi as an injudicious move that will lead to a waste of public money.

The opposition escalated after the Court on Tuesday, ordered the government to begin installing the smog towers within the next week.

Critics compare the use of the expensive and untested technology, that claims to suck up air pollutants produced by vehicles, industry and other sources, with the installation of outdoor air-conditioners to cool down global warming.

“Assuming that we can vacuum away our outdoor air pollution problem is not only a waste of tax-payers money, but also highly unscientific. If there is one lesson to learn from the COVID lockdowns, then it is the fact that we can clean our air and our act only by controlling the emissions from all the sources,” says Sarath Guttikunda, director of Urban Emissions, an air pollution information, research and analysis repository.

Even assuming 100% efficiency at all times, any outdoor smog tower can purify only 0.00007233796% of the total volume of air in the city’s 6,400 square kilometer airshed every hour, through which some 5.76 billion cubic meters of air pass every hour, contends Guttikunda.  In comparison, preventing emissions at sources such as a cement or coal-fired plant would prevent nearly 100% of emissions. He also notes that the technology was tested and failed during the 2010 Commonwealth Games in Delhi.

Smog Towers Are Cost-Ineffective Technologies
Smog obscures buildings in the distance in Gurgaon Cyber City, in Delhi

Due to the sharp limits of the technology, smog towers are ultimately far less cost-effective, in comparison to actually reducing emissions at source. At present air pollution levels, Delhi would need at least 2.5 million such smog towers to clean its air, according to one analysis carried out by Council on Energy, Environment and Water (CEEW). The city requires more sustainable solutions, as citizens in the capital inhaled dangerously toxic air for 241 days in 2019, the analysis adds.

“In no way should such unproven technologies be encouraged,’ says Tanushree Ganguly, a programme associate at CEEW, adding that money being spent on these smog towers could be used for proven measures, such as: ensuring coal power plants that generate significant air pollution comply with emission norms, ensuring a clean and reliable mass transit system, and improving waste management, to halt incineration.

“In addition to rejecting the smog tower as a solution, we should demand for evidence of its impact (or lack of it) through all our writings on this subject. We could ask for evidence on the Lajpat Nagar smog tower’s impact, the smog guns that are being used. If these are indeed solutions, then where is the evidence of the impact? Where is the data, the clear metrics to assess performance?” asks Ganguly.

“Limited resources available for air pollution action should be used for reducing emissions at source rather than testing technologies that are unproven to be effective,’ adds urban air quality scientist Pallavi Pant.

Smog Towers Haven’t Worked in China
Smog (left) obscures view of Tiananmen Square (right) in Beijing, China.

Other critics point to China, which has long experimented with smog towers many times larger than the smog tower currently in use in Delhi at Lajpat Nagar, without any documented success.

“Smog towers just end up as visible showpieces which are easier to sell as solutions to gullible ordinary citizens. When public money is scarce, especially during a pandemic, this is surely no time to experiment with untested technologies. To tackle air pollution, curbing emissions must be the top priority.” says Mihir Shah, strategic communications lead, CEEW.

“The general theme of these studies is that there are slight to modest AQ benefits in the very close vicinity of these very large towers. That is rather damning when taken in the broader perspective: a colossal misallocation of resources that will never scale,” says Joshua Apte, who holds a joint appointment at the University of California at Berkeley’s School of Public Health and Civil/Environmental engineering department.

While slamming the misallocation of resources, environmentalists also are wondering what led to the sudden enthusiasm among decision-makers for the smog towers. They say that the move will merely delay what are urgently needed measures, such as the stricter enforcement of existing laws, greater focus on renewables, less dependance on fossil fuels and more focus on health harm caused by dirty air.

“When the bucket is overflowing and your house is flooded, you don’t go looking for a mop, you turn off the tap. The only solution to pollution is to stop pumping pollutants in the air. Smog towers are a criminal waste of money and anyone with basic common sense can see that,” says Brikesh Singh of the Clean Air Collective, an unbranded collective of over 100 think-tanks, researchers and activist groups.

‘It is necessary to have enough proof to show that smog towers are an effective solution for air pollution before they start them installing them across the country,” says Meghna Amin, campaigner at Jhatkaa. Jhatkaa, an Indian NGO that builds grassroots citizen power, has been running a campaign against smog towers since March 2020, giving the science and rationale behind it.

“We are unable to understand why the government and the courts are repeatedly rejecting the opinions of environmentalists and experts who have clearly stated that smog towers are ineffective in outdoor settings. The only effective way to tackle PM2.5 is to eradicate it at its source. Any other solution is just a waste of tax payers money,” Amin adds.

Supreme Court Has Played Activist Role in Smog Tower Installation

The Court’s original order on the towers was issued in January, after two months in which Delhi reached some of the highest winter air pollution levels ever recorded, prompting public outcry. With government failing to effectively mount policies, the court began to play a more activist role in the desperate quest for solutions to clean the city’s toxic air.

The Court asked the central and Delhi governments to set up a panel to explore the feasibility of various emergency measures. Smog towers was one of the recommendations made at the time – although the panel, whose members were never publicly identified, only recommended setting up a ‘pilot” to ‘see how it fares.’  A joint proposal by the Indian Institute of Technology-Bombay, IIT- Delhi and the University of Minnesota, which had been pending with the Central Pollution Control Board, was then pulled out of the drawers.

As soon as talk of installation of smog towers became public, our air pollution advocacy non-profit Care for Air wrote an open letter to the Supreme Court, requesting it to not promote “band-aid fixes” like smog towers and other outdoor air-purifiers to deal with north India’s debilitating winter smog. At the same time, campaigning for Delhi state’s Legislative Assembly elections was getting into high gear, and the main political parties and their candidates were promising to clean the city’s polluted air.  For the first time that pollution came up as a poll agenda, following a  parliamentary debate on the subject, also a first.

While skies cleared visibly in the spring during the COVID-19 pandemic lockdown, the smog season of late fall and winter is now looming. Late fall and early winter are times when urban emissions from sources such as heating increase substantially, while weather conditions leave pollutants lingering in the city’s air. Crop burning in neighboring regions adds to the toxic mix.  Last year the pollution darkened the city’s skies for weeks on end, with 24-hour air pollution levels 10-20 times above WHO air quality recommendations.

On July 21, the Court ordered the national government, as well as Delhi state authorities, to accelerate its actions to install smog towers in Delhi.  Last week, the Court gave the government one week for the project – to be funded by public money – to begin.  On Tuesday, the government informed the Court that it had finally entered into an agreement with IIT-B, to supervise a project to install smog towers in Delhi.

The Supreme Court of India

While the Court moves may be seen by some as a valiant attempt to make some progress on cleaning Delhi’s toxic air ahead of the next crisis, analysts say the Court has overlooked the science that says that the technology only works within enclosed spaces, and has failed in other countries.

The Court, however, has largely ignored the outcry, calling out the Ministry of Environment, Forest and Climate Change and the Delhi government, over and over, giving them fresh deadlines to comply with its direction on installing smog towers in the capital city.

“We are shocked at the attitude of the respondents with respect to installation of smog towers, which were supposed to be installed within three months and for which an agreement was to be entered into and the order was passed on 13 January after obtaining the requisite reports,” the Court said in July.

In a hearing on 29 July, when IIT-Bombay displayed reservations about going ahead with the project in Delhi, a furious Supreme Court Justice Arun Mishra sternly rebuked the engineering institution, saying the court would “punish” it for withdrawing from a government project. Justice Misra even threatened contempt proceedings, saying “I can’t tolerate this nonsense.”

Environmentalists retweeted this exchange, questioning why the court was pressing this so urgently when science doesn’t back smog towers being of any use in reducing outdoor air pollution.

Air Pollution Finally a National, Political Issue
Smog in Delhi

On the more positive side, the debate has also helped thrust air pollution into the forefront of national debate – even at a time when Delhi skies have been unusually clean and blue, due to the COVID-19 imposed lockdown that reduced the city’s noxious fumes from sources such as traffic, industry and construction.

Air pollution kills nearly seven million people worldwide each year, according to the WHO’s estimates. Some 91% of those premature deaths occur 4 in low- and middle-income countries, and the greatest number in the WHO South-East Asia and Western Pacific regions.

Delhi is among the most polluted cities in the world. In May 2014, the WHO’s list of cities suffering high air pollution levels had identified New Delhi as the worst in its 1,600-city worldwide database.

Increasingly aware of the health damage that air pollution is wreaking, voters across the city and social classes have begun to demand clean air as a social and human right. But the mounting political pressure has also led to quick fix solutions, such as the smog towers. Others include “smog guns” and “vacuum cleaners” to clean outdoor air.

However, as Randeep Guleria, director of the All India Institute of Medical Sciences, New Delhi, recently said, such technologies belittle the problem on the one hand and on the other, raise false hopes among those affected by air pollution.

Existing Tower Doesn’t Work
Smog towers have not been able to reduce levels of PM2.5 particles within their vicinity.

In early January, the Gautam Gambhir Foundation installed a ‘smog tower’ in Lajpat Nagar, costing ₹7 lakh (US $9300), according to media reports. Global air pollution experts say it is not helping reduce pollution by even marginal amounts – even in its immediate vicinity.

Five experts, including scientists associated with Care for Air, visited the tower within the first three weeks of its inauguration on January 3 and found that PM2.5 some distance away from the tower was lower than PM2.5 close to the tower.

“I did a video shoot near the tower for 3 hours. There was absolutely no reduction in PM levels next to this smog tower and within a 150m radius on 3 different angles,” says Barun Aggarwal, CEO of clean air consultancy firm Breathe Easy Consultants, who visited the site on January 10 with his industry calibrated DustTrak monitor- an instrument used to accurately measure particulate matter concentrations. “I saw a man standing there with a local handheld meter taking readings. I found out he works for the company that made the tower, but he seemed completely clueless about how to take readings.”, says Aggarwal.

Things were worse three days later, on January 13, when atmospheric scientists and researchers Bhargav Krishna and Apte visited the tower. Its inbuilt monitor measured PM at 636, as photographed and tweeted by Krishna and Apte. Their photos and tweets also showed that some of the filters were already damaged and air wasn’t reaching the bottom outlets. On January 31, when Tanushree Ganguly who works on air pollution section at the Council on Energy, Environment and Water, visited the tower, it wasn’t working.

Similarly, China’s giant smog-sucking tower installed in 2016 was found to be inefficient by the China Forum of Environmental Journalists after a 50-day trial. Smog-free towers called WAYU, developed and installed by IIT and National Environmental Engineering Research Institute (NEERI) in Delhi in 2018, ended up as dustbins due to their ineffectiveness.

Smog Towers Give False Sense Of Complacency

Ultimately, observers say, installations such as smog towers provide the public with a false sense of complacency and assurance. At this point in a national pandemic where winter 2020 could lead to high levels of air pollution that compounds the impacts of the mounting incidence of respiratory infections from COVID-19, we need strong actions that yield a real and significant reduction in PM2.5 levels.

Already in February, Finance minister Nirmala Sitharaman allocated ₹4,400 crore (US$ 600 million) towards clean air in this year’s national budget, as per the recommendations of the 15th Finance Commission. The national finance commission is also considering the creation of longer-term performance based grants for India’s cities and local authorities over the coming five years. These funds should be targeted towards reducing emissions at source through improved industrial filters, faster transition to renewable energy, improved public transportation and the shutdown of old thermal power plants that do not meet emission standards – rather than expensive and unproven smog towers.


Jyoti Pande Lavakare is the co-founder of Care for Air India. She is an independent journalist focusing on environmental health issues, and a former financial and business reporter for Dow Jones Newswires, The Business Standard and India Ink. her first book, “Breathing Here is Injurious To Your Health” is due to be published by Hachette in 2020.

Image Credits: Care for Air India, Flickr: Ninara, Flickr: James Riker, Wikimedia Commons: Legaleagle86, Flickr: Ninara, Jyoti Pande Lavakare.

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