The world's largest lockdown means all factories, markets, shops, and places of worship are now closed, most public transport suspended and construction work halted, as India asks its citizens to stay home and practice social distancing. So far, India has more than 1,300 confirmed cases of Covid-19, including 35 deaths. Already, data shows that the main cities are recording much lower levels of harmful microscopic particulate matter known as PM 2.5, and of nitrogen dioxide, which is released by vehicles and power plants. PM 2.5, which is smaller than 2.5 micrometers in diameter, is considered particularly dangerous as it can lodge deep into the lungs and pass into other organs and the bloodstream, causing serious health risks.
The sudden fall in pollutants and the subsequent blue skies signal a dramatic shift for India -- which has 21 of the world's 30 most polluted cities, according to the IQAir AirVisual's 2019 World Air Quality Report.