Understanding the Dual Threat of Local Emissions and Transboundary Pollution
During the northeast monsoon season, Sri Lankans breathe air that should not exist. Real-time monitoring stations frequently show Colombo’s air pollution levels at 7–9 times higher than World Health Organisation (WHO) recommended limits. Kandy often records levels up to 10 times above safe thresholds. This is not merely a seasonal fluctuation—it is a deepening public health and economic crisis driven by both domestic emissions and the cross-border impact of regional industrial and agricultural activities, intensified by extreme weather events such as cyclones.
During peak pollution periods, Colombo’s Air Quality Index (AQI) typically ranges from 119 (“Poor”) to 153 (“Unhealthy”). Kandy follows a similar pattern, with readings between 106 and 141. These elevated levels persist from November through February, exposing millions to fine particulate matter (PM2.5) capable of penetrating deep into the lungs and bloodstream.
Cyclone Ditwah: A Wake-Up Call
On November 28, 2025, Cyclonic Storm Ditwah made landfall along Sri Lanka’s eastern coastline, leaving devastation that reshaped the national understanding of how climate change, extreme weather, and air pollution intersect.
The storm claimed over 600 lives, displaced more than 233,000 people, and affected approximately 2.3 million citizens—nearly 10% of the population. More than 1,200 landslides were triggered in the central highlands, and floodwaters submerged nearly 20% of the country’s land area.
Yet Ditwah’s impact extended beyond physical destruction. As the storm system moved across the Bay of Bengal, it altered atmospheric circulation patterns and transported large volumes of pollutants generated by neighboring countries’ industrial corridors, thermal power plants, vehicular emissions, and seasonal agricultural burning.
This phenomenon—transboundary air pollution intensified by cyclonic systems—illustrates how climate-driven extreme weather events can amplify regional pollution flows and disproportionately affect downwind nations.
According to international development studies, more than half of South Asia’s air pollution is transboundary in nature, traveling across borders through shifting wind systems.
For Sri Lanka, the northeast monsoon (November–February) brings prevailing winds that carry emissions from nearby industrial belts, coal-fired power stations, expanding urban vehicle fleets, and large-scale seasonal crop-residue burning in neighboring territories across the Palk Strait and Bay of Bengal.
This pattern has been observed repeatedly. In December 2022, Cyclone Mandous disrupted atmospheric circulation in a similar manner. Air quality deteriorated sharply across Sri Lanka, prompting nationwide school closures as AQI levels in Jaffna climbed to 294—classified as “Very Unhealthy.” Cyclone Ditwah in late 2025 replicated and intensified this pattern.
Pollutants transported during such events include:
- PM2.5 (fine particulate matter)
- Sulfur dioxide (SO₂)
- Nitrogen dioxide (NO₂)
- Ground-level ozone When cyclonic systems form, these pollutants become embedded within storm circulation and are transported across national boundaries, affecting air quality far from their original source.
Counting the Cost: The Economic Toll of Pollution
Cyclone Ditwah alone caused an estimated $4.1 billion in direct physical damage to infrastructure, agriculture, and housing—equivalent to roughly 4% of Sri Lanka’s 2024 GDP. This figure does not fully capture the longer-term health costs associated with elevated pollution levels during and after the storm.
Beyond extreme events, chronic air pollution imposes continuous economic strain:
Healthcare Burden
Increased hospital admissions for respiratory illnesses, cardiovascular diseases, and asthma place heavy pressure on medical facilities and household finances. After Ditwah, the health sector required an estimated LKR 21 billion just to restore operational capacity.
Lost Productivity
Work absences, reduced efficiency due to chronic illness, and premature mortality weaken economic output and workforce participation.
Agricultural Damage
Air pollutants damage crops, lower yields, and threaten food security—compounding climate-related losses from floods and landslides.
Tourism Impact
Hazy skies and poor air quality during peak travel seasons discourage international visitors, undermining one of Sri Lanka’s key revenue sectors.
Traffic congestion in Colombo alone is estimated to cost approximately Rs. 32 billion annually in lost productivity—without accounting for healthcare expenses tied to vehicle-related emissions.
Taken together—healthcare costs, infrastructure damage, lost productivity, agricultural losses, and environmental degradation—the cumulative economic burden of air pollution likely amounts to billions of rupees each year.
Domestic Sources: A Compounding Factor
While transboundary pollution intensifies seasonal crises, domestic emissions significantly elevate baseline pollution levels year-round.
- Vehicular emissions account for more than 60% of pollution in Colombo.
- Many vehicles remain outdated and poorly maintained.
- Public transport limitations push commuters toward private vehicles.
- Industrial emissions remain concentrated in the Western Province, which hosts nearly 70% of national industries.
- Open burning of agricultural waste and municipal garbage contributes additional particulate matter.
- Household reliance on biomass fuels for cooking exposes families—especially women and children—to harmful indoor smoke.
These internal factors interact with cross-border pollution, magnifying overall exposure levels.
Moving Forward: Solutions and Regional Responsibility
Addressing Sri Lanka’s air quality crisis requires action on multiple fronts.
Domestic Priorities
- Enforce stricter vehicle emission standards
- Expand and modernize public transportation
- Accelerate the transition to renewable energy
- Strengthen industrial emission monitoring and compliance
- Promote clean cooking technologies
Some progress has been made—such as fuel quality improvements and emission testing programs—but enforcement gaps remain.
Regional Accountability
Because a significant portion of pollution originates beyond national borders, regional cooperation is essential. Neighboring countries must strengthen emission controls in industrial zones, regulate agricultural burning practices, modernise coal-based energy systems, and adopt cleaner transport policies.
Existing regional frameworks—such as the Malé Declaration on the Prevention of Transboundary Air Pollution in South Asia—require transformation from policy statements into enforceable, measurable action plans.
Climate change adds urgency. As cyclones become more intense due to warming oceans, their ability to transport pollution across borders will increase. Mechanisms such as international “loss and damage” funding for climate-affected nations must recognise how climate-amplified transboundary pollution contributes to economic and human losses.
A Shared Airshed, A Shared Responsibility
Sri Lanka’s air quality crisis is not solely a domestic problem, nor solely a foreign one. It is the product of a shared regional airshed where emissions, weather systems, and climate impacts ignore political boundaries.
Every breath carries the imprint of decisions made both within and beyond national borders.
The path forward demands stronger domestic governance, regional emission reductions, climate accountability, and coordinated action—because clean air, ultimately, is a collective responsibility.