It is January; a month that, in north India, once fell in the season of winter, but now is more synonymous with the depths of the region’s dreaded pollution season. This month, as in recent years, a brutal combination of diverse factors has continued to coalesce to produce dire air quality in its cities, most notably in the capital New Delhi.
https://www.lowyinstitute.org/the-interpreter/choking-point-india-environment-crisis