Worsening transboundary haze in Malaysia has renewed debate over whether countries affected by smoke from overseas forest and peatland fires could pursue legal remedies under international law, while also highlighting the limitations of litigation in addressing one of Southeast Asia’s most persistent environmental challenges.
A recent letter published by the South China Morning Post raised the question of whether Indonesia could potentially face legal action over haze affecting Malaysia, after air pollution in Sarawak reached hazardous levels amid fires in neighbouring Indonesian territory. The discussion comes as ASEAN continues to strengthen regional mechanisms aimed at preventing and managing transboundary haze.
Hazardous Haze Returns to Sarawak
At the end of August, Serian in Sarawak recorded an Air Pollutant Index reading of 476, while Kuching, Samarahan and Sri Aman also registered readings above 300, the level classified as hazardous under Malaysia’s air-quality system.
Conditions subsequently deteriorated further. On September 4, Malaysia declared an emergency in Serian after the API exceeded the national emergency threshold of 500, with readings reaching around 519 to 521. The declaration allowed stronger measures to protect residents from the health effects of the worsening haze.
The ASEAN Specialised Meteorological Centre had already raised its alert level for the southern ASEAN region in August, reporting widespread moderate-to-dense smoke haze from hotspot clusters in Kalimantan and transboundary haze drifting northward from West Kalimantan.
The latest episode demonstrates how quickly land and forest fires in one part of Southeast Asia can create public-health, economic and environmental consequences across national borders.
Could One ASEAN Country Sue Another Over Haze?
The legal question is more complicated.
The SCMP commentary noted that international law recognises circumstances in which a state may bear responsibility for environmental harm that crosses its borders. Broadly, establishing state responsibility would require demonstrating that the relevant conduct is attributable to the state and that an international legal obligation has been breached.
ASEAN’s own Agreement on Transboundary Haze Pollution (AATHP) reflects a similar principle. The treaty states that countries have sovereign rights over their natural resources but also carry responsibility to ensure that activities within their jurisdiction or control do not cause environmental damage or harm to human health in other states.
However, proving legal responsibility for haze would be difficult.
Forest and peatland fires may involve private companies, small-scale land clearing, individual actors, weather conditions and broader environmental factors. Establishing a direct legal connection between particular fires, government actions or omissions and specific damage experienced abroad could therefore require extensive scientific and legal evidence.
International Court Action Would Face Significant Obstacles
The possibility of bringing a case before the International Court of Justice (ICJ) also involves jurisdictional hurdles.
The court does not automatically have authority over every dispute between countries. Jurisdiction generally requires an accepted legal basis allowing the court to hear the particular case.
The SCMP letter referred to the Ecuador v Colombia aerial herbicide spraying case, launched in 2008 after Ecuador alleged that Colombian aerial spraying near their border had caused damage to people, crops, animals and the environment in Ecuador.
That case demonstrates that cross-border environmental disputes can reach the ICJ, but it never produced a final judgment on state responsibility. Ecuador withdrew the proceedings in 2013 after the two governments reached an agreement that resolved the dispute and created mechanisms including an exclusion zone and joint monitoring arrangements.
The precedent therefore illustrates both the possibility of international environmental litigation and the importance of negotiated solutions.
ASEAN Treaty Prioritises Consultation and Cooperation
Within ASEAN, the existing legal framework strongly emphasises cooperation rather than courtroom confrontation.
Signed in Kuala Lumpur in 2002 and entering into force in 2003, the ASEAN Agreement on Transboundary Haze Pollution commits Member States to prevent, monitor and mitigate haze caused by land and forest fires through national action and regional cooperation. Indonesia deposited its ratification in 2015, making the agreement applicable across all then-ASEAN Member States.
The agreement requires countries to monitor fire-prone areas, control land and forest fires, exchange information and take preventive measures against activities that could produce transboundary pollution.
Crucially, Article 27 states that disputes concerning the interpretation, application or compliance with the agreement are to be settled amicably through consultation or negotiation.
This reflects ASEAN’s traditional preference for regional diplomacy and consensus-driven problem-solving.
Prevention Remains More Effective Than Litigation
The renewed legal debate highlights an important distinction between accountability after damage occurs and preventing the damage in the first place.
Haze can affect respiratory health, disrupt schools and workplaces, reduce visibility, damage tourism and create broader economic costs. By the time air pollution reaches emergency levels, communities may already have experienced substantial disruption.
That makes early hotspot detection, stronger fire prevention, peatland management, land-use enforcement and rapid firefighting potentially more effective than relying primarily on legal remedies after pollution crosses borders.
ASEAN governments have reaffirmed their commitment to the Haze-Free Roadmap 2023–2030, the ASEAN Peatland Management Strategy and the full implementation of the regional haze agreement, with the broader objective of achieving a haze-free ASEAN by 2030.
Regional Coordination Takes on Greater Importance
The 2026 haze episode is occurring against particularly challenging weather conditions.
The ASEAN Specialised Meteorological Centre warned in August that persistent dry weather and strengthening El Niño conditions could increase the risk of severe transboundary haze across the southern ASEAN region.
That increases the importance of real-time information sharing and coordinated preventive action among Indonesia, Malaysia, Singapore, Brunei and other potentially affected countries.
In July, Indonesia hosted the 27th Sub-Regional Ministerial Steering Committee on Transboundary Haze Pollution, bringing together regional governments to strengthen implementation of the ASEAN haze agreement and prepare for heightened fire risks.
Such mechanisms could become increasingly important as climate variability raises the frequency and intensity of conditions conducive to forest and peat fires.
Accountability Must Extend to the Source of Fires
The debate is also broader than government-to-government responsibility.
Private companies and individuals involved in illegal or irresponsible land clearing can play an important role in creating fire risks. Effective haze prevention therefore depends heavily on domestic law enforcement, corporate accountability and transparent monitoring of land concessions.
This means regional solutions must operate at several levels simultaneously: national authorities must enforce environmental laws, businesses must implement responsible land-management practices, and ASEAN institutions must strengthen coordination when pollution crosses borders.
Greater use of satellite monitoring and publicly accessible hotspot data could further improve transparency by helping governments identify fire clusters earlier and establish clearer evidence about their origins.
Looking Ahead
The question of whether Indonesia could theoretically be sued over haze affecting Malaysia does not have a simple yes-or-no answer.
International environmental law provides principles that could potentially support claims involving serious cross-border harm, but questions of jurisdiction, attribution, causation and proof of legal breach create substantial obstacles. ASEAN’s own haze agreement also directs Member States towards consultation and negotiation rather than adversarial dispute settlement.
The more immediate challenge is ensuring that ASEAN’s existing commitments translate into effective prevention.
The latest haze emergency in Sarawak demonstrates that transboundary air pollution is not merely an environmental inconvenience. It is a regional public-health and economic issue capable of closing schools, disrupting daily activity and pushing communities into emergency conditions.
As Southeast Asia works towards its goal of a haze-free ASEAN by 2030, stronger enforcement, faster information sharing, better peatland and forest management and deeper cross-border cooperation may ultimately deliver more practical protection than litigation alone.
The renewed legal discussion nonetheless carries an important message: as the social and economic consequences of transboundary pollution grow, expectations for accountability — whether through domestic enforcement, regional mechanisms or international law — are likely to increase alongside them.
