Thread by @rishdotblog

Sigh. Delhi's air is going to crap again. Many reasons for this, but stubble burning is a massive contributor, and it is mostly concentrated in Punjab

Penalizing farmers is not the solution to this – this is actually a legislative and *groundwater* issue (more below)

Stubble burning has gone up a lot in the last 30 days, as it does around this time ever year, because farmers have to clear their fields and burning stubble is the most efficient way to do this.

@ShekharGupta did a great video about this 3 years ago:

And as bad as the graph above seems, it is likely to get much much worse. We are likely to see far more stubble burning in the next 2 weeks, is history is any indicator

This is actually a groundwater issue. Punjab has laws that prohibit farmers from planting paddy in May, in order to prevent groundwater levels from going low before the monsoons

So they can only plant paddy from mid-June onwards. And that has cascading effects

Because of this, they are only harvesting the crops in late October/early November (when wind speeds in North India slow down to a crawl and temperatures drop).

And not in September (which is windier and warmer, so particulate matter doesn't stay suspended in the air)

This also means that there is no time to plant Rabi crops (like wheat) before winter. So burning the paddy stubble is the the quickest and most cost effective way to clear their fields

All of this leads to days like today, when the air is scarcely breathable. People are annoyed, emotions are high, schemes like "odd-even" are suggested, but fundamental issues are swept under the rug :/

The same point made with satellite imagery, via @sanjeevsanyal:

https://twitter.com/sanjeevsanyal/status/1588012984336805888