On certain days, Colombo’s skyline is barely visible. This is due to a thick haze that envelops Sri Lanka’s commercial capital, resulting in low air quality conditions. The fouled air is making people tear and cough more without knowing what causes such irritation.
Santhanam Mary has been a municipal worker for 13 years. Her daily job is to clean an area near the heart of Colombo. “Even though we physically clean the streets, there’s so much pollution around us,” she told Mongabay.
Over the years, Mary recalled falling sick more frequently. “We [municipal workers] get frequent headaches, itchy eyes and cough and cold-like symptoms. We were asked to wear face masks when working, but it is difficult to wear them for a long time,” she said.
Meanwhile, the latest real-time air quality monitoring map by the National Building Research Organization (NBRO) shows a reading of 82 micrograms per cubic meter in Badulla, the largest city in Uva province and 52 mcg per m3 in Kotte in Western province. This may answer a question Mary did not ask: the reasons for increasingly falling ill.
In issuing warnings, the NBRO has said that Air Quality Index (AQI) fine particulate matter (PM2.5) readings between 101 and 200 are unhealthy for sensitive or at-risk groups. These groups include children, pregnant women, the elderly and people with preexisting heart or lung conditions.
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A key reason for lung cancer is smoking, but air pollution could make people more vulnerable. On the other hand, people already suffering from lung diseases may find it difficult to breathe due to low air quality.
Duminda Yasaratne, professor, University of Peradeniya
According to the index, readings between 0 and 25 mcg per m3 (AQI PM2.5 of 0-50) indicate satisfactory air quality. The World Health Organization’s PM2.5 guideline recommends an annual average of 5 mcg per m3 to minimise long-term health risks.
In early March, air pollution levels in Kolonnawa, Anuradhapura and Galle surged to unhealthy levels, leading citizens to complain about respiratory problems due to poor air quality. “From Feb. 28 to March 3, AQI levels exceeded 100 in almost all parts of the country,” Vernika Ranwaka Arachchi, director of air quality, noise and vibration monitoring at the Central Environmental Authority (CEA), told Mongabay.
“Once the haze entered the country, we observed how the wind conditions contributed to making the haze stagnant, not allowing it to move away. We collect the daily average of pollutants, including PM2.5, PM10, sulfur dioxide, carbon monoxide, ozone and so on. There were readings close to 150 PM2.5, the dominant pollutant, which remained over four days. We generally expect air quality levels to deteriorate during March due to changes in wind directions. If the readings exceed 150 of PM2.5 level, we opt to implement the contingency response action plan,” she said.
Contingency response
The plan recognises three trigger levels for PM2.5 and PM10 pollution episodes: alert level (150 mcg per m3), warning level (200 mcg per m3) and emergency level (300 mcg per m3).
“Once the CEA declares an emergency episode, controlled actions such as sharing of information through social media channels to create public awareness will be done. Even though the readings in most parts of the country are moderate right now, we continue to monitor the situation and evaluate the readings daily,” she added.
A 2020 review of air pollution studies by Oliver Ileperuma, professor emeritus of chemistry at the University of Peradeniya, shows between 1997 and 2003, levels of SO2, O3 and NO2 have steadily increased while the CO2 levels have plunged.
Exposure to these pollutants can result in inflammation, oxidative stress and immunosuppression while impacting vital organs, including the lungs, heart and brain.
According to Lareef Zubair, principal scientist at the Federation for Environment, Climate and Technology (FECT) who holds a doctorate in fluid turbulence, nonlinear dynamics and diagnostics, there is a systematic rise in low air quality since the 1990s. “We have measurements on the ground in Colombo starting in the 1990s by the CEA. There is a seasonal trend which peaks when there are events such as agricultural burning in India or the Norochcholai coal power plant emissions. There is a greater frequency of air quality exceeding various thresholds over the past three decades,” he told Mongabay.
According to the 2025 IQAir World Air Quality Report, Bangladesh and Pakistan ranked among the most polluted countries, driven by industrial emissions, agricultural burning and heavy traffic, causing millions of premature deaths annually. Sri Lanka was ranked 42 among 143 countries by the index in 2025.
Meanwhile, Ranwaka Arachchi identified PM2.5 as the dominant pollutant in many Asian countries, a mixture of solid particles and liquid droplets found in the air.
“It has been established that this impact is transboundary. Based on backward trajectory modeling data, it is possible to establish the origin. We monitor pollution trends throughout the year, but during February and March, this trend peaks. We expect haze conditions to emerge from time to time till end of March,” she added.
Malé Declaration
With the aim of addressing the transboundary impact of air pollution, in 1998, Sri Lanka became a party to the Malé Declaration on Control and Prevention of Air Pollution and it’s Likely Transboundary Effects for South Asia. The declaration focuses on monitoring, policy measures and enhancing the environment through regional cooperation.
But according to Zubair, scant attention has been paid to this agreement throughout. “There is a defensiveness on the part of Indian officials and scientists who have been resisting attribution of regional air pollution to activity in the Indian subcontinent,” he explained.
Zubair noted nothing significant could be done to improve the air quality caused by transboundary impact, in the absence of India changing its role.
“The Malé Declaration is not operational despite cordial and reciprocated good relationships between Sri Lanka and India. India itself faces much worse pollution particularly in the Northern Plains below the Himalayas. Air pollution has become a ‘wicked problem’ in India, and the government is not able to reduce pollution so far, something China has managed to achieve to an extent. But the attribution of Sri Lanka’s pollution to the Indian subcontinent — including sometimes Pakistan — is all quite evident from the wind and pollution transport data,” the climate scientist added.
In 2018, respiratory illnesses accounted for the third leading cause of hospital admissions in Sri Lanka. According to medical experts, Sri Lanka has one of the highest asthma prevalence rates globally, reasons for the island to try to keep its air clean.
Speaking to Mongabay, Duminda Yasaratne, professor in respiratory medicine at the University of Peradeniya, said air pollution could cause someone without lung conditions to develop diseases such as asthma or pulmonary fibrosis. “A key reason for lung cancer is smoking, but air pollution could make people more vulnerable. On the other hand, people already suffering from lung diseases may find it difficult to breathe due to low air quality. We therefore advise patients with asthma, for instance, to avoid walking on the road during daytime and to wear face masks,” he said.
Particulate matter less than 10 mcg is known to threaten people’s health with their possible entry into lungs and sometimes the bloodstream. “When people are exposed to PM2.5 for a long period of time, they develop cardiovascular diseases, heart attacks and even paralysis. They can easily develop respiratory illnesses,” Yasaratne added.
He also said a person’s lungs develop between the ages of 10 and 20 years. After the age of 25, even with exercise, there will be no growth. So, children need sports and quality air to breathe. If they breathe low-quality air, their lungs may not fully develop. By the age of 30 or 40, their lungs may deteriorate and will be vulnerable to respiratory diseases, he added.
Meanwhile, Ranwaka Arachchi added that recommendations to address air pollution at the regional level have been submitted to the Ministry of Environment, Foreign Ministry and South Asia Co-operative Environment Programme. “We are planning to have discussions at South Asia level to discuss about this issue in order to minimise impact on public health. But we cannot resolve it single-handedly. We also hope that we would be able to achieve certain targets at least by 2030,” she said.
This story was published with permission from Mongabay.com.
