Sri Lanka is facing growing challenges in managing air pollution, particularly in urban and industrialized areas like the Western Province. The country bears a considerable health burden due to air pollution, with the average annual exposure to fine particulate matter (PM2.5) reaching 20.0 µg/m³—four times higher than the WHO guideline. In 2019, 48 deaths per 100,000 people were attributed to fine particle pollution, amounting to approximately 11,000 premature deaths nationwide . The health impact is widespread, with 13% of chronic obstructive pulmonary disease, 12% of strokes, 12% of tracheal, bronchus, and lung cancers, 11% of ischemic heart disease, 11% of type 2 diabetes, 10% of lower respiratory infections, and 5% of neonatal disorders in 2021 linked to outdoor PM2.5 pollution . Despite these impacts, Sri Lanka has made progress by achieving 5 out of 9 global air quality targets—including clean production incentives, vehicle emission standards, sustainable agricultural practices, air quality management strategies, and the establishment of air quality standards—though serious challenges remain in reducing population exposure and strengthening health protections.
Industrial emissions remain a notable source of air pollution in Sri Lanka, particularly from approximately 970 high-emission industries—such as oil refineries, power plants, cement factories, and agriculture-based facilities—mainly concentrated in the Western Province. Challenges in this sector include outdated technologies, limited financial resources, and weak compliance monitoring. Vehicular emissions also contribute significantly to air pollution. Although a national vehicle emission testing program operates through over 460 centres, its impact is constrained by poor fuel quality, outdated testing protocols, and limited technical capacity. Public awareness of air pollution and its health effects is generally low, and constrained funding has slowed progress on key policy initiatives, including the adoption of renewable energy and electric mobility. Sri Lanka has introduced several regulatory measures over the years, including the National Ambient Air Quality Standards in 2008, vehicle and fuel regulations between 2003 and 2018, and stationary source emission controls in 2019. More recently, the country has taken steps to promote cleaner transport through the development of an E-Mobility Policy, conversion of three-wheelers to electric vehicles, and regulation of charging infrastructure and battery disposal. Efforts are also underway to scale up solar energy generation, aiming to achieve 4,000 MW from land-based and rooftop sources by 2023.
Seasonal analysis of PM2.5 concentrations in Colombo from 2000 to 2024 reveals distinct trends influenced by monsoonal patterns. PM2.5 levels are consistently highest during the dry months of November to March, with monthly averages often exceeding 30–40 µg/m³. In contrast, concentrations drop significantly during the wetter months of May through September, frequently falling below 15 µg/m³. Maximum monthly PM2.5 variability also peaks in the dry season, with several observations surpassing 70 µg/m³, indicating episodes of acute pollution. This pattern underscores the seasonal nature of air quality in Colombo, where dry weather conditions, reduced atmospheric dispersion, and various emission sources—including possible biomass or agricultural burning—contribute to elevated pollution levels, frequently breaching WHO safety thresholds.
Yearly PM2.5 levels in Colombo, Sri Lanka, indicate a stable but consistently elevated level of air pollution over the past two decades. Concentrations have generally ranged between 21–24 µg/m³, with only minor year-to-year fluctuations and no clear long-term declining trend. Despite being lower than in many other South Asian cities, Colombo's PM2.5 levels remain well above the WHO's 2021 air quality standard of 5 µg/m³.