Several studies showed a correlation between long-term exposure to air pollution and increased likelihood of death from COVID-19, likely due to poor lung health. Even short-term improvements to air quality may be helping to reduce the number of deaths from other respiratory illnesses. Cities across the world have understood that now is the time to move towards clean mobility and have already begun to remodel their urban space with more emphasis on walking and bicycling. Cleair route finders calculates alternative routes with the lowest concentration of pollutants along each route made available to citizen via the Cleair app.

S12 East-West corridor route shows. The route is mostly polluted throughout as it starts from Howrah Station, central Kolkata, and pollution level eases as we move to Salt Lake Route close to Sealdah Railways station is severely pollution

S9 North-South corridor route shows. The route is more polluted in the northern part as well as in the Rash Bihari Avenue. This route runs along the Hooghly river and it shows a lower level of pollution alongside the river, And towards the south-western end

Pollution exposure quantification for the region is done by counting the number of days for which the daily pollution mean is greater than poor levels. For each of the twenty-one stations, we define a region around the station that defines the pollution state for that region. The best measure of pollution in that region is approx one km radius of the station.

The range of count of the days of bad pollution exposure varied from 35 to 60 for all regions combined and the range is color codes as in bins of five i.e. 35-40 (inclusive) Light Green, 40-45 (inclusive) Green, 45-50 (inclusive) Light Red, 50-55 (inclusive) Dark Red and 55-60 (inclusive) Dark Red

The figure shows a coarse co-relation between COVID19 severity and the bad pollution exposure levels. The figure also shows the COVID19 hotspots in the more polluted regions.