Suman Chakrabarti, Md Tajuddin Khan and Samuel Scott
Respiratory infections are the most common chronic disease in children globally and a leading cause of death in developing countries. This situation is exacerbated by air pollution.
Air pollution in northern India, mainly New Delhi and the neighbouring states, is exacting a toll on the health of residents, making global headlines and highlighting the severity and extent of this public health disaster in one of the world’s fastest-growing economies.
A contributory factor to air pollution in northern India is the harmful practice of crop residue burning — when farmers burn the crop residue to clear fields before sowing a new crop. Although banned by the Indian government in 2015, this practice remains prevalent in many parts of the northern Indian states of Punjab, Haryana and Uttar Pradesh.
In our study recently published in the IJE, we found a link between crop residue burning and acute respiratory infection and estimated its economic and health costs. We analysed health data from more than 250,000 people of all ages residing in villages and cities in India. Using NASA satellite data on fire activity to estimate the health impact of living in areas with intense crop burning, we found that the frequency of reported hospital visits for acute respiratory infection symptoms paralleled the number of fires observed by satellite: as crop burning increased, respiratory health worsened.
Crop residue burning was the leading risk factor among those we examined for acute respiratory infection in India, and economic losses associated with the health effects of crop residue burning were estimated at about USD35 billion per year. When combined with firecracker burning, the economic losses are nearly USD152 billion, or 1.7 per cent of India’s GDP over five years.
In districts where crop residue burning is intense, residents, especially children under 5 years of age, are three times more likely to visit the hospital for symptoms of acute respiratory infection. We found that it wasn’t only the residents of Delhi, but also women, children and men living in the rural areas of Delhi’s neighbouring state, Haryana, who are the first victims of crop residue burning. Much of the public discussion about ill effects of crop residue burning ignores this immediately affected vulnerable population and focuses only on residents of Delhi.
During certain times of the year, coinciding with the onset of winter in northern India, levels of airborne particulate matter in Delhi spike to 20 times the safe threshold proposed by the World Health Organization. Smoke from burning of crop residue in northwestern India has been estimated to contribute up to 78% of the enhancement in small particulate matter in Delhi on certain days.
Our study found that exposure to vehicular pollution, open drains, cooking with biomass and urban living are some of the other leading risk factors for acute respiratory infection.
Even though biomass burning is practised in the United States and several developed countries in Europe, it has become a major health concern in India due to its negative impact on air pollution. The Indian government has demonstrated an interest in combating air pollution and respiratory illness but, so far, has fallen short in addressing the air quality crisis.
As Indian farmers face tough times, convincing them to change their practices will require full cooperation from the highest levels of government. Our study suggests that targeted government initiatives to improve crop disposal practices are worthy investments. Programs and policies must simultaneously address indoor and outdoor pollution through a combination of bans and agricultural subsidies. Other important interventions for improving respiratory health are increasing household access to clean cooking fuels, electricity and improved drainage systems.
Despite efforts from the Indian government, farmers continue to burn crop residue because of a lack of convenient and affordable alternatives. Eliminating crop burning will not only improve human health but will also contribute to soil and plant biodiversity and reduce greenhouse gas emissions.
Chakrabarti S, Tajuddin Khan M, Kishore A, Roy D, Scott SP. Risk of acute respiratory infection from crop burning in India: estimating disease burden and economic welfare from satellite and national health survey data for 250 000 persons. Int J Epidemiol 2019; Feb 28. https://doi.org/10.1093/ije/dyz022.
Samuel Scott is a researcher at the International Food Policy Research Institute, New Delhi, India. Suman Chakrabarti and Md Tajuddin Khan are doctoral candidates at the University of Washington and Oklahoma State University, respectively.