The decision of the Bruhat Bengaluru Mahanagara Palike (BBMP) to install 500 outdoor air purifiers across various junctions speaks volumes of the deterioration of the ‘Garden City’, which is witnessing increasing pollution levels.

The primary causes for the worsening air quality are vehicle emission, construction dust and road dirt, aided by the depletion of green cover and vanishing water bodies. Air purifiers absorb fine dust particles and release clean air.

An air purifier installed at Hudson Circle some time ago on an experimental basis has been found to be successful, prompting the BBMP to replicate the project in other highly polluted spots.

The civic body will not shoulder any financial burden as the project will be undertaken by a private company as part of its corporate social responsibility. However, the purifiers, which cover a radius of 60 feet each, will offer only a small respite, as corporation officers estimate that 44,000 such towers are required if the entire city has to be covered. The world’s largest air purifier, a 100-meter high tower is located in the Chinese city of Xian, and initial studies have indicated an improvement in the air quality over a 10 sq km area. A future version of the tower is expected to touch 500 meters, with an impact radius of 30 sq km.

According to a study by Urbanemissions.info assisted by researchers from the Centre for the Study of Science, Technology and Policy, air pollution in the city will continue to rise alarmingly with PM 10, that is, particulate matter less than 10 microns in size, recording a rise of 74% by 2030. PM 2.5, or fine dust, which is considered the most dangerous of pollutants as it slips through the body’s natural defences and enters vital organs through the bloodstream, is estimated to increase by 54%.

A marginal increase in PM levels can cause minor discomfort in breathing in sensitive people, while a severe rise can affect even the healthy and seriously impact those with existing diseases.

While air purifiers are welcome as they will help people breath easy at least in a few polluted junctions, there is an urgent need for some permanent measures. The first step should be to reduce vehicle population on city roads, which currently stands at around 80 lakh units, by strengthening public transport and speeding up the much-delayed suburban rail project. The focus should also be on providing clean fuel and checking vehicle emission levels.

Above all, it is high time the authorities realised that trees are natural air purifiers and that there can be no better solution than re-greening the city.