As industries remained shut and vehicles were off the roads, an analysis by the System of Air Quality Forecasting and Research (SAFAR) showed that there was a significant decline in pollutant levels – mainly nitrogen dioxide, PM 10 and PM 2.5 - during the three lockdown periods in Pune, as compared to last year during the same period. Scientists at SAFAR monitored levels of pollutants during the first three phases of lockdown and compared it with the levels recorded last year. A similar analysis has been done for Delhi, Mumbai and Ahmedabad. Nitrogen dioxide (released during traffic emissions), PM 2.5 (atmospheric particulate matter that has a diameter of less than 2.5 micrometers) and PM 10 (atmospheric particulate matter with a diameter of less than 10 micrometers) are among some of the major pollutants which, when exposed to for a long period of time, can cause respiratory disorders. Dr Gufran Beig, project director of SAFAR, told The Indian Express that the analysis found 67.9 per cent reduction in nitrogen dioxide levels during the first lockdown as compared to levels recorded last year. In the second lockdown, it found 79.6 per cent reduction in nitrogen dioxide levels and in the third lockdown, the reduction was 53.3 per cent. PM 2.5 levels fell by 16.4 per cent during the first lockdown, by 22. 4 per cent during the second lockdown and 3.1 per cent during the third lockdown. PM 10 levels reduced by 28.8 per cent during the first lockdown, 35.0 per cent during the second lockdown and 20.9 per cent during the third lockdown period. Because of the lockdown, there has been a decline in emission levels and at some places, the reduction in pollutants was high, said Dr Beig. This was also possibly because there were rain spells which also help wash away the pollutants, he said. Air pollution has increased India’s health burden, making it more vulnerable to threats like Covid-19. The pandemic puts people suffering from respiratory conditions that are worsened by air pollution, like asthma and chronic obstructive pulmonary disease (COPD), at increased risk of death and complications. Nine out of 10 people breathe air the WHO deems too polluted, causing an estimated 4.2 million premature deaths every year. However, experts say improvement in air pollution levels should not be seen as a silver lining but an opportunity to understand the background levels in cities when major sources are on hold. With most activity on halt, and the subsequent low levels of pollution these days, it is clear that air quality can improve in a matter of weeks. At a webinar organised recently by Climate Trends, Dr Sagnik Dey, associate professor, Centre for Atmospheric Sciences, Indian Institute of Technology-Delhi, said that every source apportionment study shows that there are eight key sources of pollution in India - power plants, vehicles, industry, household, brick kilns, open burning, diesel generator sets and dust (from construction, soil, re-suspended and trans-border). Of these eight sources, only four were shut down during lockdown - vehicles, industrial activity, brick kilns and construction activity. This reduction in pollution in India during the lockdown has come from these four major sources and that needs to be taken into account in the National Clean Air Programme, he said. “If we can control vehicular, industrial, brick kilns and construction activity, we can reach PM 2.5 and PM 10 targets in the near future,” said Dr Dey
