To tackle pollution, smog tower to come up in Delhi

On Monday, the Supreme Court directed the Centre and the Delhi government to draw up a comprehensive plan in 10 days to install ‘smog towers’ across the capital to deal with air pollution.

4 min readNew DelhiNov 26, 2019 07:35 AM IST First published on: Nov 26, 2019 at 01:20 AM IST

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In Delhi, the 20-metre high tower would trap particulate matter of all sizes suspended in the air. (Express Photo by Abhinav Saha)

A ‘smog tower’ being planned for Delhi as an experiment would create a “clean air zone” around it with an estimated 50% reduction in particulate matter, experts involved in the project told The Indian Express Monday.

On Monday, the Supreme Court directed the Centre and the Delhi government to draw up a comprehensive plan in 10 days to install ‘smog towers’ across the capital to deal with air pollution.

The project is being headed by the Indian Institute of Technology (IIT) Bombay in collaboration with IIT-Delhi and the University of Minnesota. The latter helped design a similar tower of over 100 metres in China’s Xi’an city. The Central Pollution Control Board is also involved with the project.

Explained

What is a smog tower

Smog towers are structures designed to work as large-scale air purifiers. They are usually fitted with multiple layers of air filters, which clean the air of pollutants as it passes through them. China, which has been battling air pollution for a few years, has two smog towers — in its capital Beijing and in a northern city called Xi’an. The latter is dubbed as the world largest smog tower and has reportedly brought down PM 2.5 by 19% in an area of around 6 sq km in the tower’s vicinity.

In Delhi, the 20-metre high tower would trap particulate matter of all sizes suspended in the air. “Large-scale air filters will be used in the towers, which will draw in the air through fans installed at the top before passing it through the filters and releasing it near the ground,” said an IIT-B expert in-charge of the project.

An estimate made by project experts of the tower’s impact on air quality shows it would reduce 50% of the particulate matter load in an area 1 km in the direction of the wind, as well as 200 metres each along the sides of the tower and against the direction of the wind.

The filters being installed in it would use carbon nanofibres as a major component and would be fitted along its peripheries, project experts said, adding that the project is only focused on reducing particulate matter load at present. The tower is expected to start running before next winter.

Finding a suitable location is one of the main aspects of the project, said IIT-D Professor Mukesh Khare, who is on the project advisory board. He added, “If, for instance, the tower is installed near AIIMS, the air in that area would be cleaner.” A location is yet to be decided for the tower.

Professor Khare also said the tower design would consider Indian meteorological and air pollution conditions: “In China, the meteorology is different, their sources are mainly industrial. In Delhi, we have road dust, vehicular emissions and biomass burning among the sources.”

The project is estimated to cost around Rs 12-13 crore. A project member said it would be a “demand-based instrument” to reduce severity of air pollution.

He added that an assessment of the impact made by this tower on local air quality would be done to estimate how many such units would be required across Delhi.