India's capital shuts schools because of smog

Levels of PM2.5 pollutants -- dangerous cancer-causing microparticles that enter the bloodstream through the lungs -- were recorded at 57 times above the World Health Organization's recommended daily maximum on Sunday evening. They stood around 39 times above warning limits at dawn on Monday, with a dense grey and acrid smog smothering the city. The city is blanketed in acrid smog each year, primarily blamed on stubble burning by farmers in neighbouring regions to clear their fields for ploughing, as well as factories and traffic fumes.