Delhi Implements Emergency Measures to Combat Air Pollution
Delhi has been grappling with severe air pollution during the winter season for over a decade, posing a significant threat to the health of its residents, especially children and the elderly. The city experiences high levels of toxic particles that become trapped in the air when temperatures drop and wind speed decreases. These particles originate from sources such as vehicle emissions, industrial chimneys, and agricultural residue burning in neighboring states. In an effort to address this issue, the city authorities have once again initiated emergency measures, including reducing road traffic, banning farm fires, and activating smog towers to improve air quality. However, the effectiveness of these towers has sparked a renewed debate.
So, what exactly are smog towers? Delhi residents are familiar with air purifiers, which use high-efficiency particulate air filters (HEPA) to cleanse indoor air. Smog towers operate on a similar principle but on a much larger scale. These towering structures, reaching up to twenty meters in height, are equipped with thousands of filters and aim to capture pollution particles, thereby improving air quality in densely populated areas. While the technology behind smog towers is relatively simple, they require extensive maintenance and come with a hefty price tag. For instance, the smog tower in Connaught Place, one of Delhi’s prominent business centers, cost approximately $2.5 million to install.
The idea of smog towers originated in India, with at least two such units being deployed in Delhi. These towers are activated when air quality worsens. In 2020, a small smog tower was tested in a bustling market, demonstrating the need for 2.5 million filters to clean Delhi’s air each day. However, this operation would come with a staggering cost of over $20 billion, which is 2.5 times the annual budget of Delhi.
Despite the initial optimism surrounding smog towers, research suggests that their impact on air quality is limited. As these towers operate outdoors, they struggle to clean a sufficient amount of air within a short period. The filtered air released by the towers quickly mixes with the surrounding pollution, negating any improvements. A recent study conducted by researchers at IIT Bombay examined the smog tower in Connaught Place and found that it only achieved 50% efficiency in cleaning the air, which dropped to 30% at a distance of 50 meters from the filters and a meager 10% when 500 meters away. Furthermore, the researchers discovered that the structure holding the filters was not tightly sealed, allowing polluted air to bypass the filtration system.
While local authorities in Delhi and beyond still support the idea of smog towers, the prevailing scientific consensus suggests that they are expensive and ineffective in combating air pollution.
