Southeast Asia has long struggled with haze caused by forest fires, and the latest episode has raised the regional alert level to Level 3. On August 26, the ASEAN Specialized Meteorological Center issued the alert as smoke from fires in Kalimantan, Indonesia, spread across borders. This situation highlights the challenge of managing environmental issues that affect multiple countries. While Indonesia has the primary responsibility for preventing and fighting fires on its territory, the issue has now become a test of whether ASEAN, the regional grouping of Southeast Asian nations, can help its members manage problems that no single country can fully control. Malaysia and Brunei Darussalam have already agreed to elevate the matter to the ASEAN level for discussion and action. Transboundary haze is not a new phenomenon in Southeast Asia. Historical records show that smoke from fires in Indonesia has affected neighboring countries since at least the 1970s. Some of the most severe episodes occurred in 1997 and 2015, when massive fires led to widespread health issues and economic disruption. Scientists have identified several factors contributing to these fires, including human activities such as land clearing through burning and environmental conditions like dry, degraded peatlands. Peat, a type of soil rich in organic matter, can burn underground for long periods, producing thick, persistent smoke that is hard to extinguish. Weather patterns, such as those associated with El Niño, can also worsen the situation by creating prolonged dry conditions that help fires spread and carry smoke across borders. Indonesia is at the center of the problem, as many of the fires that generate transboundary haze occur on its territory, particularly in the islands of Sumatra and Kalimantan. This places the main responsibility on the Indonesian government to prevent fires, enforce environmental laws, and hold those responsible accountable. Indonesia has laws and institutions in place to prevent forest and land fires, and research shows that the country has strengthened peatland protection efforts since 2016. However, the recurring fires show that turning regulations into effective action remains a challenge. This is especially difficult when economic interests, local practices, and extreme weather conditions interact in complex ways, making fire prevention difficult to implement consistently. ASEAN has been aware of the haze problem for decades and has taken steps to address it. In 1997, after the severe haze episode, member states adopted the Regional Haze Action Plan to improve prevention, monitoring, and regional coordination. In 2002, they signed the ASEAN Agreement on Transboundary Haze Pollution (AATHP), which created a legal framework for preventing and responding to haze. Indonesia was the last country to ratify the agreement, doing so in 2015. However, studies suggest that the effectiveness of these agreements is limited by the "ASEAN Way," a principle of regional cooperation that emphasizes national sovereignty and non-interference. This means that while the haze is a shared regional issue, the authority to address its causes remains largely within individual countries, creating a challenge for regional action. To be more effective, ASEAN does not need to become a supranational authority. Instead, affected countries can use ASEAN channels to push for stronger enforcement from Indonesia, and public pressure can increase the cost of inaction. ASEAN can also improve transparency by sharing data on fire hotspots, fire activity, and government responses, making it easier to track progress. Practical collaboration, such as joint firefighting efforts and early warning systems, can also help. These measures would not replace Indonesia's responsibility but would support it. The recurring haze shows that national responsibility and regional consequences often do not align neatly. While Indonesia must lead in preventing fires within its borders, neighboring countries cannot wait for the next crisis, and ASEAN cannot treat each haze episode as routine. The goal should be to strengthen regional cooperation so that preventing fires becomes a priority, not just a reaction to a crisis. After decades of recurring haze, Southeast Asia may not need a new agreement. It needs to enforce its existing commitments more effectively.