<![CDATA[Transboundary haze arising from forest and land fires in Kalimantan exposes limitations in the enforcement of regional environmental obligations under the ASEAN Agreement on Transboundary Haze Pollution (AATHP). This study examines Indonesia’s preventive obligations, the legal consequences of absent compulsory enforcement mechanisms, and possible reforms within ASEAN. Normative legal research employed statutory, conceptual, and case approaches, analyzing the AATHP, ASEAN Charter, Indonesian environmental legislation, Articles on Responsibility of States for Internationally Wrongful Acts (ARSIWA), and relevant international decisions. The analysis identifies duties of prevention, monitoring, cooperation, and due diligence under Articles 3, 4, and 7–9 of the AATHP. International responsibility requires an attributable state act or omission constituting a breach; cross-border haze alone does not establish liability. Article 27 provides consultation and negotiation without compulsory adjudication or a specific compensation mechanism. Treaty silence does not automatically displace generally applicable responsibility and reparation rules under Article 55 of ARSIWA, although enforcement remains constrained by jurisdictional consent. The study proposes an additional protocol introducing a non-adversarial compliance committee, measurable due diligence indicators, differentiated compensation arrangements, and time-bound dispute settlement. Stronger domestic enforcement and regional evidence sharing across Southeast Asia could connect existing obligations with more effective accountability while preserving ASEAN’s consensual framework. ]]>
