2 However, Delhi sees very bad air pollution days even without stubble burning

This becomes clear if one reads the number of active fires in Punjab and Haryana with the AQI in Delhi in November 2021. From November 5 to 13, there were more than 4,000 fires on all days but one. Expectedly, the AQI in Delhi was in the “severe” range (above 400) on seven of those nine days. On the other hand, the AQI was severe even in the November 26 to November 28 period, even though only 120, 75, and 20 farm fires were recorded on these days respectively. This shows that while a ban on stubble burning will certainly help, it is no guarantee of no “severe” days.