pollution of delhi: point of view: stubble cultivation is not an insignificant source of pollution, and a “simple” solution exists


Last Monday, the GoI informed the Supreme Court that stubble burning contributes only 4-10% to air pollution in Delhi and is not a major source of pollution. But was this statement correct? The answer depends on how the data is interpreted.

If one considers the annual average data, as the GoI did in its affidavit, the contribution of stubble burning is less than 10% and can be considered insignificant. However, if we consider the days, weeks and months when the stubble is burned, their contribution is very high. For example, data from the Indian Government’s Air Quality and Weather Forecasting and Research System (SAFAR) shows that on November 7, 48% of PM2.5 (particles with a diameter of 2.5 micrometers or less) in Delhi were due to stubble burning, and it was 33% in the week of November 7-13.

Thatch is not in fashion

Studies indicate that during peak burning months, their contribution ranges from 20 to 30%. Now, this 20-30% contribution causes Delhi’s Air Quality Index (AQI) to drop from “poor” to “severe” from October to November and leads to all kinds of shouting, including interventions. courts. It is therefore a serious mistake to regard stubble burning as an insignificant source.

Scientifically speaking, stubble cultivation is a polluting activity of short duration and high intensity. The equation is simple: the 15 to 20 million tonnes of paddy stubble burned in Punjab, Haryana and western Uttar Pradesh for two months emit PM2.5, or 4 to 5 times the amount. PM2.5 emissions from all vehicles operating on Delhi’s roads in the entire year. The intensity of emissions is so high that even if a small fraction of them reach Delhi, the city’s poor air quality deteriorates further. This fact has been established by all scientific studies. Therefore, it is time that we stop bickering over the numbers and focus on identifying the right solutions, because the promoted solutions do not work.

For this, it is crucial to understand that stubble burning is a technological problem. Farmers using combines – which combine harvesting, threshing, collecting and winnowing in one process – are the most likely to burn stubble, unlike those who practice manual harvesting. This is because combines cut the grainy part of the rice plant – the ear – and leave about 30 cm of stalk intact in the field. Thus, a farmer must either manually cut the stalk, or use another machine, practice in situ management, or burn it. Of these, engraving is preferred as it is the simplest option.

The other important factor is the use of straw. In Punjab and Haryana, basmati paddy is mainly harvested by hand, as its straw is highly valued as fodder for animals. The incidence of burning in basmati fields is therefore very low. During this time, the non-basmati straw is not used as fodder for animals and is therefore burned.

So what has the government done to combat stubble burning? In addition to penalizing some farmers (a political hot potato, especially in an election year), the government has encouraged in situ management of crop residues by providing a 50-80% capital grant to purchase agricultural machinery. Over the past four years, the GoI has spent over 2,000 crore on these grants. But these machines largely accumulate dust due to cultural, practical and economic factors.

It is essential to understand that these subsidized agricultural machines are not primarily designed to stop stubble burning. Instead, they are intended for no-till agriculture, in which thatch can be kept in the field and recycled into the soil. The no-till method has significant ecological benefits, including improved soil quality and reduced water consumption. The elimination of thatch burning is a co-benefit.

Stub the burning question

The challenge, however, is that this is an entirely new method of farming for Indian farmers. They have been practicing tillage for centuries and cannot be expected to switch quickly to a new method. In addition, it has a higher initial cost. Despite the subsidies, farmers have to pay an additional fee of about 2,500 per acre to use these machines, which most cannot afford.

Thus, the use of combines, weak market links for non-basmati stubble, and the promotion of expensive technologies that require a long period of adoption collectively support the practice of stubble burning. What we need instead is a scientific, affordable and culturally adaptable solution.

The simplest and most affordable solution is to redesign combines to cut paddy straw from the base of the plant to remove the stem. Straw can be sold or used as mulch. A baler can also be integrated with combines to wrap the straw, which can then be easily transported and sold.

The good news is that some newer versions of the combine – the semi-feed combine – already incorporate these features and are sold in small numbers. So why aren’t other companies modifying their combines and why is the GoI neglecting this simpler solution? The answer seems to be economic interests. Both conventional combine harvester manufacturers and field machine manufacturers benefit from this policy. After all, if you can sell several machines to solve a simple problem, why promote a simple solution.

Occam’s Razor is a problem-solving principle that states that the simpler solution is more likely to be correct than the complex solutions. This is certainly the case with stubble burning. By promoting complex solutions instead of simpler ones, we have botched the stubble burning problem.


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