October 6, well into the annual gloomy descent into polluted territory, the Delhi government launched its anti-pollution campaign—Yuddh Pradushan ke Viruddh (War on Pollution). As part of this, the installation of a smog tower in the bustling Connaught Place has also been approved. It would reportedly cost Rs 20 crore. It comes against the backdrop of the Supreme Court reprimanding the Delhi government for not complying with its earlier order to install smog towers in the national capital. This tower will likely take 10 months to come up.
Interestingly, this is not the first time the idea of ambient air purification is being endorsed as a solution for Delhi’s pollution woes. In 2010, an air filter was installed in Connaught Place during the Commonwealth Games and eventually removed. Last year, amidst much fanfare, a smog tower was installed in Lajpat Nagar. In 2015, ambient air purifiers called Wind Augmentation and Purification units (WAYU) were installed in Mumbai, Delhi and Bangalore. Unfortunately, there is no evidence of the impact of these installations.
A smog tower claims to filter out dust and particulates from polluted air, thereby releasing clean air. Like an indoor air purifier, the effectiveness of a smog tower is determined by the tower’s Clean Air Delivery Rate (CADR) and the efficiency of the filters it employs. Theoretically, the higher its CADR and efficiency, the higher the effectiveness of the tower. The tower at Connaught Place, a souped-up version, is being touted as yet another experiment. However, smog towers cannot solve Delhi’s air pollution problem, and here’s why.
A 60-m-tall smog tower in Xian, China.
First, air cannot be contained in the open. In a recent scientific publication—Can We Vacuum Our Air Pollution Problem—the authors argue that air is not static over a city. While an indoor air purifier can be designed for a closed room with a fixed volume of air, millions of cubic metres, influenced by pollution from neighbouring areas, pass through the city boundaries every second.
Second, evidence from Xian, China, is not promising. In 2016, a 60-metre-tall air purifying tower was installed there. The Xian tower’s impact has “purportedly” been observed within an area of 10 sq km around the tower, which means that 1,000 such towers costing approximately $2 million each would be needed to clean all of Xian’s air. The technology employed in the Xian tower can be traced to the University of Minnesota. Results of a numerical simulation carried out by researchers at the university convey that even in a scenario where the downtown area of Beijing is surrounded by eight of these towers, a minimal amount of clean air would reach Beijing downtown. Quite naturally, the tower has been dubbed an “eyewash” by Chinese media.
Third, assuming the tower works to a limited extent, millions of them would be needed to make a real dent in an airshed like Delhi, which is influenced by local and regional sources. According to an analysis by the Council on Energy, Environment and Water (CEEW), the impact of the Lajpat Nagar smog tower is limited to a 15-ft radius and at least 2.5 million of those towers are needed to clean Delhi’s air, with financial requirements running into thousands of crores.
Let’s look at the issues plaguing Delhi’s fight against pollution. The Delhi Pollution Control Committee (DPCC), the authority responsible for managing environmental pollution in Delhi, is grossly understaffed. As per a recent report in a national daily, the DPCC team responsible for spot checks and enforcing pollution standards has only 37 officials. The power plants in our country are yet to meet the emission standards notified in 2015. In the recent Swachh Surveskshan Awards, the three prominent municipal corporations of Delhi—South, North and East—were ranked 36th, 43rd and 46th, respectively, among urban areas in India on the basis of cleanliness, highlighting the need for vast improvements in the city’s waste management. Almost 30 per cent of Delhi’s population relies on public transport, but the city is still short of at least 4,000 buses. Clearly, there are multiple avenues where the money needed to set up smog towers can be better spent.
It is important to note that while the Delhi government has maintained its position on smog towers being an experimental solution, cities like Gurgaon have taken a cue and are planning to pump tens of crores into this proverbial white elephant. According to the State of Global Air 2020 Report, in 2019, air pollution killed 116,000 infants in the first month of their lives in India. All of India’s 1.4 billion people breathe air with PM2.5 concentrations that well exceed the World Health Organization’s standards. This is time for concerted action against the sources of pollution, not experimental green-washing.
(Views are personal)
Programme Associate at the Council on Energy, Environment and Water (CEEW), an independent, not-for-profit policy research institution