> The ban on crop burning (main cause of Delhi's pollution) was central to the farm bill. But protesting farmers (widely supported in the west) opposed it, and the bill died despite having democratic approval (both national opinion and sufficient votes)

Then why is Delhi's air quality consistently poor, unhealthy, severe and hazardous even when there is no crop burning? https://www.aqi.in/us/dashboard/india/delhi/new-delhi

Of course we need to do something about crop burning, but is it the "main" reason? Nope.