Satellite imagery from the first week of May showed that concentration of Nitrogen Dioxide (NO2) — a pollutant released due to burning of fuels and organic waste — has increased drastically over the past few weeks after the wheat crop was harvested in the states of Punjab, Haryana and Uttar Pradesh at the end of April.

Farmers use stubble burning as a quick but dirty method to quickly clear off the straw left behind after a harvest as removing straw manually is time consuming and expensive. The burning is often blamed for the severe air pollution in Delhi during the winter months.

While the stubble burning in winters is more visible as smog, the practice goes largely unnoticed in the summer months as the heat and winds dissipate pollutants like Particulate Matter (PM) and NO2 over the Indo-Gangetic plain.

Satellite pictures show that NO2 concentration — indicated in shades of green and red — jumped across North India from the last week of April (Pic I) to the first week of May (Pic II)

NOx concentration

NOx concentration

The lack of NO2 pollution in large parts of the country shown in Pic I is due to the drastic fall in tail-pipe emissions during the national lockdown. In Pic II which depicts the green areas show increased NOx concentrations despite the lockdowns being in place. Also note that the North East shows an extremely high concentration of NO2 constantly as there are many large capacity coal-powered power plants operating in the region.

More worryingly, NO2 levels are the lesser of the pollutants which get released due to stubble burning. The rise in levels of Carbon Dioxide and Carbon Monoxide are alarming! A report by Anmol M Dua for the Bhajan Global Impact Foundation said that according to the Ministry of Agriculture and Farmers’ Welfare, in Haryana, Punjab, and Uttar Pradesh 23 million tonnes of paddy stubble was burnt in 2017 and

  • carbon dioxide levels increased by 70 percent

  • carbon monoxide levels increased by 7 percent

  • nitrogen dioxide levels increased by 2.1 percent

Why does summer stubble burning go unnoticed?

In the summer months of April and May, wheat crops which are planted during the winter are harvested and the land has to be cleared for the upcoming paddy crop. Farmers use wheat residue as fodder for cattle and it’s only the stalk that is set on fire. The paddy residue is not used as fodder as it’s unfit and hence farmers burn both the paddy stalk and straw close to autumn every year.

Wheat harvesting is at its peak in the last week of April and first week of May, due to which NO2 levels have spiked precariously. While these emissions are more visible in the winters, in summer months the heat dissipates the pollutants. This is why the problem of stubble burning receives media attention mostly in in the winter months of November and December.

Also as tail-pipe emissions have fallen across India in the past month due to Covid-19 lock downs and NO2 pollution from vehicles and industries have reduced, the emissions from stubble burning can be noticed more clearly.

Reports suggest that authorities in Punjab and Haryana are finding it hard to enforce bans on farm fires as state police forces are largely engaged in maintaining the national lockdown.

Here is a district-by-district breakdown of stubble burning in Punjab in the last month.

Stubble buring across Punjab

Stubble buring across Punjab

This year, owing to the novel Coronavirus, farmer unions have come together to stop stubble burning as bad air quality can worsen the health of those suffering from Covid-19. However reports show that wheat stubble burning incidents have gone up by 6 percent compared to last year in the state.

To be fair to the farmers, the share of farm fires to Delhi’s pollution, depends on daily instances of fires and the weather conditions and using alternative methods of disposing of stubble are expensive, according to this Mongabay report. And the state machinery has been active in creating awareness, enforcing the rules through fines and giving incentives for mechanical management of straw. But the carrot-and-stick approach can only get us so far. The problem of stubble burning now needs economically-feasible solutions not more governance.