Coverage of smoke events across the region tends to cluster around breathing-related ailments, shuttered classrooms, grounded aircraft, and reduced visibility. Plants grown for food face ongoing exposure to polluted air, yet they receive notably less attention in environmental health discussions than other categories of living things affected by the same conditions.
Particulate matter, ground-level ozone, and nitrogen oxides all contribute to air-quality deterioration, with haze representing just one measurable indicator among several. Exposure to these contaminants has been linked to reduced harvests, diminished nutritional value, and stunted plant development, placing atmospheric pollution within the broader conversation around reliable food supply alongside its well-documented effects on human health.
Microscopic pores known as stomata dot leaf surfaces to regulate gas exchange, while the energy driving photosynthesis arrives from light absorbed by the plant. Elevated pollution levels in the atmosphere interfere with a plant's ability to absorb light, stunting development, lowering harvests, and degrading the overall standard of produce. Fine particles in the air can transport harmful substances that build up inside plants, a pattern observed with particular frequency in food crops cultivated close to cities and industrial zones.
Thick atmospheric haze intercepts a notable share of solar radiation before it reaches the earth's surface. Smoke from the 1997 Indonesian forest fires blocked enough sunlight to suppress plant photosynthesis, drawing down harvests of rice, fruits, vegetables, and long-cycle perennial crops. Occurrences of haze in 2026 point to that vulnerability remaining in place.
Haze from fires blanketed wide stretches of the Mekong sub-region — including eastern Myanmar, northern Thailand, Laos, and Vietnam — as ASEAN's monitoring noted cross-border smoke drifting through the area between December 2025 and May 2026. Across the southern portion of the ASEAN region, fire-detection tallies recorded during the opening six months of 2026 ran roughly 86 per cent above the figures logged over the equivalent stretch of 2025. Smoke originating from Kalimantan and Sumatra had, by the close of September 2026, spread across maritime Southeast Asia, with haze reaching into Malaysia, Singapore, Borneo, and as far as the Philippines.
Farm land at risk of smoke exposure can stretch well beyond the boundaries of any given burn zone, given that smoke columns routinely drift for hundreds of kilometres before dispersing. Farmland across the ASEAN bloc covers a total area of roughly 126 million hectares.
Drawn from ASEAN Specialised Meteorological Centre haze-footprint data for 2026 cross-referenced against Food and Agriculture Organisation cropland figures, a preliminary calculation points to somewhere between 50 and 70 million hectares of agricultural land across the region — a share equivalent to roughly 40 to 55 per cent of Southeast Asia's total farmed area — as having faced potential exposure to elevated haze concentrations during both the northern and southern episodes recorded that year. What the figure captures is exposure alone — actual crop losses fall outside its scope. No evidence-based evaluation of haze's toll on farming output has been conducted across the ASEAN region.
Reduced visibility from haze represents just one of several atmospheric conditions that can affect air quality. Ground-level ozone — an invisible atmospheric compound — has been documented to lower harvests and diminish the nutritional and physical attributes of food crops. Over the four decades from 1981 through 2021, ground-level ozone took a measurable toll on American crop production, with modelling data pointing to a 3.5 per cent drag on maize harvests and a 6.1 per cent shortfall in soybean output. Projections put the toll on American agriculture during 1984 at somewhere between two and three billion dollars.
Not all crops respond to stress in the same way — rice, soybeans, beans, peanuts, and horticultural varieties each tolerate or succumb to environmental pressures at different thresholds. Studies carried out on Vietnamese farms have recorded how both rice and peanut varieties respond to the conditions under examination. When yield figures slip even slightly across farmland spanning millions of hectares, the cumulative shortfall at national or global scale can reach a substantial total.
Within the bloc, cross-border air pollution has long been handled as a shared environmental concern rather than a matter for any single nation. Three regional policy instruments — the Second Haze-Free Roadmap 2023–2030, the ASEAN Peatland Management Strategy 2023–2030, and the ASEAN Investment Framework for Haze-Free Sustainable Land Management — each carry provisions that may advance cleaner practices across agriculture and commodity production. The ASEAN Food, Agriculture and Forestry Sectoral Plan 2026–2030 leaves a notable gap by not drawing explicit connections between air quality on one hand and agricultural output, productivity losses, and food security on the other.
Five areas have been identified as warranting the most immediate attention. Across ASEAN member states, both public agencies and private-sector actors have been identified as standing to benefit from combining crop-distribution maps with data on fire activity, ozone levels, and PM2.5 concentrations to build a clearer picture of agricultural exposure. Field experiments and sustained monitoring of staple crops over time have been identified as approaches that would allow researchers to put concrete numbers on the scale of those losses.
Satellite data, low-cost sensor networks, farm weather stations, and crop-modelling tools have been identified as potential conduits through which environment and agriculture bodies could embed air-quality advisories directly into digital farming platforms. Both government bodies and private-sector organisations have been called upon to step up plant-breeding programmes and crop management strategies that address tolerance to ozone exposure, particulate pollution, drought, heat, flooding, and elevated salinity levels. Regulatory frameworks that make open-field residue burning a less attractive option than soil incorporation, composting, biochar production, animal feed use, or other biomass applications form the core of the fifth recommended action on agriculture's contribution to haze pollution.
Weather patterns expected across the final months of 2026 and into the opening stretch of 2027 have been flagged for their potential effects on food production. When El Niño patterns overlap with the dry season across southern parts of the region, rainfall deficits in the archipelagic zones and heightened burning activity can each amplify the others in a self-reinforcing cycle. Surveillance efforts covering those crops have been identified as warranting the greatest weight on varieties tied to both economic output and food supply — a list spanning rice, maize, cassava, soybean, vegetables, fruits, coffee, cocoa, rubber, and oil palm.
Crafting sound farm policy under shifting and unpredictable conditions depends on reliable data about atmospheric haze levels, ground-level ozone concentrations, and how each of those pollutants affects agricultural output. Adapting existing findings to Southeast Asia has been identified as a priority, given that the region's crop varieties, atmospheric pollutant combinations, climatic conditions, and agricultural practices diverge considerably from the contexts in which the bulk of existing research was conducted.
Healthy soil, water, biodiversity, and a stable climate form the foundation on which farming depends. Advocates have put forward the argument that air quality deserves a place alongside other foundational natural resources within the framework of farming and land-use policy. Measuring the tonnage of agricultural output lost to air pollution — particularly during haze events tied to an intensified El Niño cycle — has been described as a pressing data gap for ASEAN member states to address.
Teng holds a visiting senior fellowship with the Climate Change in Southeast Asia Programme at ISEAS – Yusof Ishak Institute. He also holds a consultancy role at NIE International, the international arm operating under Nanyang Technological University Singapore.
