India’s capital Delhi has the dubious distinction of topping the list of the most polluted cities. A recent study also showed that the air pollution in the city is not an isolated case as other Indian cities also suffer from heavy pollution. The list includes Ludhiana, Gwalior, Kanpur, Allahad, Patna and Raipur. The problem is not limited to the cities, however, as studies have shown that 75% of air-pollution related deaths were from the rural areas.
Burning Rice After Harvest
Most of the cities that experience heavy pollution are located in northern India. According to Chandra Venkatraman, a chemical engineering professor of the Indian Institute of Technology Bombay, the second biggest source of air pollution in the northern states is agricultural residue burning. Every year from November onwards, rice farmers in the northern Indian states like Punjab and Haryana burn the stubble left over from harvesting rice. This helps the farmers clear the fields for the next harvest. Unfortunately, the haze adds to the pollution in the cities.
A 2016 study conducted by the Indian Institute of Technology in Kanpur estimated that air quality in Delhi could lower by 90% if the habit of rice burning will not be stopped. This bold move may be difficult for Indian farmers to understand and accept, but is crucial to the survival of millions of people living in the area.
One measure of air quality used by the World Health Organization (WHO) is PM2.5, which is based on the concentration of microscopic particles smaller than 2.5 micrometers in diameter. These are considered harmful because they can be inhaled and lodged in the lungs and are not naturally expelled. From the lungs, these particles can also pass further on to other organs.
The WHO considers a PM2.5 index higher than 25 to be unsafe. In November 2017, Delhi had an air quality index of 1,000, measured at the US Embassy.
Regional Disputes Worsen the Problem
One of the major causes of the seasonal smog and pollution is agricultural in nature, and Delhi is not the only area which is affected. Other regions and cities also experience these deleterious effects. The problem could not be solved simply by prohibiting the farmers from burning rice fields. The territorial boundaries have made this a political dispute between the chief minister of Delhi against the chief minister of Punjab and Haryana.
Planting rice in Asia is a tedious process which involves flooding the rice paddies before plowing the soil. The paddies are harrowed afterwards, which means running a large comb-like mechanism to break the muddy soil further. It is in this process that the burned stubble is broken down further. The land is leveled to ensure that the seedlings are planted at an even depth. A level soil also ensures that the water is also even. After leveling, either the paddies are seeded, or seedlings are planted. The burned stubble mixes with the soil during the tilling process.
Burning rice paddy stubble (also known as agricultural biomass residue) is called Crop Residue Burning (CRB) and has long been considered as a major health hazard. According to different sources, it is a major source of pollution, and contributes between 12% to 60% of PM concentrations. It also does not help the soil to recover, causing the loss of topsoil nutrients like nitrogen, sulfur, potassium and phosphorus. With less topsoil layer nutrients, there is a greater need to use commercial fertilizers.
The Punjab region produces between 18-20 million tons of paddy straw while the Haryana region produces two million tons. About 85% to 90% of the paddy straw is burned in the field. Punjab also produces 20 million tons of wheat straw, and farmers have also begun burning these rice by-products.
Proposed Solutions and Alternatives
The Air Act of 1981 made CBR a punishable offense, with local village officials charged with implementing the law. A penalty is imposed on the farmer who commits this offense. However, as expected, legislation has not been able to prevent this practice.
One solution for the farmers is a government subsidized purchase of a farm machine which would help in planting rice without the need to burn the stubble left over from the previous harvest. The machine would allow planting while tilling the soil, which would also streamline the planting process. The concept would be a revolutionary process as current rice planting methods have not changed since it was first planted.
The use of paddy straw in biomass-based power plants has also been suggested. Current operational and planned projects in Punjab use up to 0.04 million tons of straw. The Central Electricity Regulatory Commission (CERC) has set up tariffs in Punjab to serve as incentives to erect biomass powered electric plants. The tariff for paddy straw is higher than that of wind and solar energy production.
Paddy straw can also be made into charcoal pellets or briquettes, as well as used as fuel for industrial baking kilns in producing bricks, as well as in the production of ethanol. A process for the procurement of paddy straw from farmers have to be but in place for the process to happen.
The Punjab region already has various projects in different stages of development in the pipeline to use paddy straw in bio-refineries for ethanol. Paddy straw can be an excellent raw material for biomass pellet fuel for industrial uses, including the replacement of coal. Other uses of paddy straw is manufacturing paper, cardboard, and making packing materials. These methods and tools require equipment and processes to produce. As packing materials, these can potentially replace synthetic materials.
Paddy straw has a lot of opportunities to help the community, and at the same time reduce air pollution in India’s northern regions. The opportunity exists for the methods and processes to be established by the small communities for the alternative economic usage of this raw material.
China’s Takes the Tech Approach
India isn’t the only country facing this problem. China, with its bulging population, has also been battling problems with pollution for years now, but not just from burning rice. Reports from the University of Exeter have revealed that air pollution and chemical use in farms have negatively impacted the ability of crops to absorb and store carbon from the atmosphere.
More than 295 million vehicles emit 44.725 million tons of pollutants each year. The situation has led local scientists to adopt bold and unconventional farming methods to secure the country’s food supply. ‘Plant factories’, indoor vertical farms that grow produce requiring minimal energy and land resources as seen as the most viable solution to the problem. These self-contained systems are not exposed to choking air pollution levels which are said to be five times over the safe levels declared by the WHO.
So far, the efforts have been successful. Nowadays, indoor patches of bok choy, tomatoes, celery, and lettuce produce more than 40 to 100 times more crops than an open field farm.
Vertical farms could be the answer to the problem of meeting food supply, but it does not address the problem of pollution.
Everyday Practices Contribute to Pollution
Besides the post-harvest burning of rice fields, another major source of pollution in India is residential biomass burning. These include firewood, dried cow dung, and other materials burned to cook food or for heating. Open fires with cow dung or firewood as fuel is the most common method of cooking in India. The use of coal as fuel for power generation is the second biggest source of air pollution. Anthropogenic dusts, transportation, diesel fuel and brick kilns are other major sources of pollution.
In 2015, there were more than a million deaths in India, equivalent to 25% of the total deaths worldwide due to air pollution. Further studies on pollution and air-pollution related deaths estimate that there would be up to 1.6 million deaths annually by 2030. If aggressive measures were put in place soon, up to 1.2 million deaths could be averted annually by 2050.
Crop reside burning is a big source of pollution, but it’s only one of many factors that add up to the problem. One way to prevent this type of agricultural burning is to educate farmers that rice straw can be used to create other industrial and commercial products. This opportunity can improve the air quality in the northern cities of India as well as provide rice farmers additional income.
In the meantime, they can take a cue from China and look at other agricultural solutions which involve technology.