A smog tower is just pseudoscience: Experts

Though IIT-B is back onboard to complete the court-project smog tower at Anand Vihar, experts say Delhi needs over 2.5 million smog towers for any effective change in AQI levels
A man dyes a fabric on a pavement next to the smog tower (a 20-feet-tall air-purifier) at Lajpat Nagar. (Photo | EPS)
A man dyes a fabric on a pavement next to the smog tower (a 20-feet-tall air-purifier) at Lajpat Nagar. (Photo | EPS)

Every winter, Delhi- NCR is covered in a thick blanket of smog and the Environmental Pollution (Prevention and Control) Authority’ has to declare a public health emergency. After AQI levels escalated following the annual episode of stubbleburning last year, the Supreme Court instructed the Delhi government and the Central Pollution Control Board (CPCB) to erect smog towers.

The Indian Institute of Technology, Bombay (IIT-B) got onboard, by submitting a proposal to the CPCB. By April, smog towers under testing mode were to be installed at Anand Vihar and Connaught Place. But due to the subsequent lockdowns, the deadline was flouted. On July 29, IIT-B backed out of the project, but came back onboard after the court threatened contempt action.

However, experts are unsure of the effectiveness of solitary smog towers spread few and far inbetween Delhi-NCR. “This is pseudoscience the Supreme Court believes in. There is no scientific evidence that says smog towers actually help. If smog towers are the solution, we will need lakhs and lakhs of smog towers. The judiciary should base its decision on evidence and experts’ comments, instead of notions and intuitions,” says Activist and Swechha Founder Vimlendu Jha, adding, “In January, Gautam Gambhir put up a smog tower at Lajpat Nagar. Did anybody do a survey to figure out whether it had any impact? No.” Polash Mukerjee, Air Quality & Climate Resilience, NRDC India, quips, “If we go by the Lajpat Nagar tower, we will need 2.5 million more towers to tackle the problem just in Delhi.”

India took the decision of installing smog towers following China’s footsteps, but experts say China is implementing strong pollution control rules across sectors, which India hasn’t. “Beijing fixed its problem of high pollution levels by also looking at industries, public transport and pushing bicycles. Visually, the tower looks appealing, that it will engulf all the pollutants, but that is not the reality,” adds Jha.

Environmentalist Jai Dhar Gupta observes that “Smog towers have failed everywhere in the world. There is no reason it will work here. They (SC) are pretending to put forth a solution that is not even a solution.” Smog towers can solve problems very small areas around them, but not the whole city, says Sumit Sharma, Director, Earth Science and Climate Change Division, TERI. “It will only act upon the air in its vicinity of a few 100 metres.”

How do smog towers work?

Jyoti Pande Lavakare, Co- Founder, Care for Air, says, “There are different technologies used to clean the air. One uses HEPA filters, (used in indoor air purifiers), which filters PM 2.5 particles. Another uses electrostatic precipitators that attract PM 2.5 particles and collect them at the base of the tower. Both would work in closed spaces, but are ineffective in open spaces. We don’t know what technology the IIT-Bombay or University of Minnesota is using because that hasn’t been shared in public. One smog tower costs around Rs 7-8 lakh, so you can do the math. Even worse, if we use filters to clean the air, who is going to dispose of them once they get clogged?”

What is the solution?

The only way to reduce air pollution is to reduce emissions at the sources, explains Gupta. “Our problem is so severe and we have no option but to move away from fossil fuels. We know what percentage of emission comes from which source. Be it industrial, biomass burning, paddy burning or vehicular pollution. When we know the sources, why are we continuing with these hogwash things?” adds Gupta. He shares that we can also incentivise good behaviour and penalise bad behaviour.

“For instance, people driving electric cars can be given benefits, and those driving diesel cars can be penalised. In a month, paddy burning will start in Afghanistan, Pakistan and Punjab, and the whole area from Pakistan to Bangladesh will turn into a hellhole. The SC has imposed a ban on stubble burning, but it is not being enforced properly,” shares Gupta. Instead of controlling the pollution when it has dispersed in the air, we should try to control it at the source, adds Sharma.

Lavakare says, “There is a technology called flu gas desulphurisation – it is like putting a sieve on the chimney outlets of coal fired power plants. All thermal power plants must have these Those who don’t should be penalized.” If public money is being spent, and the Court is fixated on smog towers, she suggests they should be placed in enclosed spaces with high footfalls, like hospitals, underground metro stations and indoor stadiums. Meanwhile, Sri Harsha Kota, Assistant Professor, Department of Civil Engineering, IIT-Delhi, informed that IIT-Delhi’s role is just to evaluate the tower after it is operational.

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