A recent study titled ‘Surface ozone pollution-driven risks for the yield of major food crops under future climate change scenarios in India’, conducted by researchers at the Indian Institute of Technology (IIT) Kharagpur, in India, has brought attention to a growing but under-acknowledged challenge facing India’s agriculture: surface ozone pollution. This airborne pollutant, though not as widely recognized as other environmental threats, is emerging as a major concern for crop health and yield, particularly in regions that form the backbone of India’s food production.
Understanding the Role of Surface Ozone in Agriculture
Unlike the protective ozone layer high in the atmosphere, surface ozone exists at ground level and is harmful to living organisms. It forms when sunlight reacts with pollutants like nitrogen oxides and volatile organic compounds emitted from vehicles, industrial activities, and burning of biomass. Once formed, it becomes a powerful oxidant.
For plants, especially food crops, this means stress. Surface ozone enters leaves through stomata—tiny pores involved in gas exchange. Once inside, it damages cells and tissues, disrupting normal growth and reducing photosynthetic efficiency. Over time, this can result in visible damage such as yellowing and spotting of leaves, and more crucially, a decline in productivity.
The IIT Kharagpur study, led by Prof. Jayanarayanan Kuttipurath and his team at the Centre for Oceans, River, Atmosphere and Land Sciences (CORAL), delves into how this form of pollution is affecting India’s staple food crops—wheat, rice, and maize. Their findings raise concerns not only about local food security but also India’s role in the global food market.
A Closer Look at the Impact Zones
The study highlights that the Indo-Gangetic Plain and central India are among the most affected regions. These areas are key agricultural zones, responsible for producing a significant portion of the country’s food grains. According to the researchers, ozone exposure levels in these regions could exceed safe thresholds by up to six times, putting enormous pressure on the health of crops and the livelihoods of millions of farmers.
Using data from the Coupled Model Intercomparison Project phase-6 (CMIP6), the researchers analyzed historical trends and projected the impact of continued ozone exposure under future climate scenarios. Their models suggest that if current emissions trends persist without strong mitigation efforts, wheat yields alone could decline by as much as 20%. Rice and maize may also see drops in productivity of around 7%, figures that could seem modest at first glance but are devastating at a national scale where every percentage point affects millions of tonnes of food.
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A Roadblock on the Path to Eradicating Hunger and Poverty
One of the most concerning revelations from the study is the link between air pollution and India’s broader development goals. The researchers argue that rising ozone pollution is directly hindering progress toward the United Nations Sustainable Development Goals (SDGs), particularly Goal 1 (No Poverty) and Goal 2 (Zero Hunger).
Food security in India is not only about producing enough—it’s about ensuring that agriculture remains viable and resilient amid multiple challenges, from population growth to changing climate patterns. A steady decline in yields, combined with increasing input costs and erratic weather, could put small and marginal farmers in a particularly vulnerable position. These are the very communities that policies aimed at ending poverty and hunger are designed to support.
Moreover, since India is a major exporter of food grains to countries in Asia and Africa, the ripple effects of declining productivity will not remain confined within its borders. Any disruptions in India’s ability to produce and export could also affect international markets, making it a concern that extends beyond national boundaries.
Current Policies Leave Farmlands Behind
While the government of India has taken steps to address urban air pollution—most notably through the National Clean Air Programme—rural and agricultural regions have largely been left out of the conversation. These areas, despite being critical to the country’s food production system, have not received equivalent attention in terms of air quality monitoring or pollution control.
The IIT Kharagpur study makes a case for a shift in this approach. It suggests that agricultural policies must begin to account for air quality as a factor influencing crop productivity. This means extending air quality monitoring networks into rural areas and tailoring mitigation strategies that are suitable for farmlands.
Unlike urban emissions, a significant portion of rural ozone precursors may originate from practices like stubble burning and the use of diesel-powered irrigation pumps. Tackling such sources will require a mix of regulatory oversight, technological support, and on-ground education and engagement with farmers.
What Needs to Change on the Ground
To reduce the threat posed by surface ozone, emissions of its precursors must be brought down significantly. This involves controlling emissions from both industrial and agricultural sources, improving fuel quality, encouraging cleaner farming techniques, and investing in air quality monitoring infrastructure in rural areas.
But addressing the issue goes beyond emissions control. It also requires agricultural extension services to include information about ozone exposure in their advisories, supporting farmers with crop varieties that are more resistant to oxidative stress, and possibly rethinking cropping patterns in the most affected zones.
Researchers argue that timely policy interventions can prevent much of the projected damage. But time is a critical factor. Delayed action could result in long-term losses that would be harder to reverse, particularly as climate change continues to add layers of complexity to agricultural planning.
An Unseen Challenge That Can No Longer Be Ignored
Surface ozone may not be visible to the naked eye, but its effects on agriculture are becoming increasingly hard to ignore. As India strives to secure its food systems and improve rural livelihoods, paying attention to this silent stressor is no longer optional.
The study by IIT Kharagpur serves as a timely reminder that the health of crops is intricately linked to the quality of air they are grown in. Addressing this issue will require collaboration between environmental scientists, agricultural planners, policymakers, and farmers themselves. Only then can the full picture of agricultural sustainability come into focus—one where invisible pollutants are taken just as seriously as the visible ones.