S-E Asia experiencing one of the worst haze episodes due to fires in Indonesia: WMO director

Transboundary haze is air pollution from fires that crosses national borders. It matters because smoke produced in one country can affect people, transport and daily activities across an entire region. In this episode, fires in Indonesia became the main source of smoke affecting Singapore, Malaysia and the Philippines.

The key mechanism is wind. Smoke released by burning vegetation and cleared land can travel with prevailing winds over the sea and into neighbouring countries. Churchill said about half of the world’s smoke haze came from Indonesia during the seven days from Oct 8, based on satellite-linked Fire Emissions Watch data.

Singapore recorded 13 consecutive days of unhealthy PSI readings. Malaysia and the Philippines were also affected. The haze may continue for weeks or months, depending on when winds change and rain reaches the fires. Regional warnings and shared firefighting could reduce the cross-border damage.

The haze episode was exceptionally severe. Ben Churchill, the World Meteorological Organisation’s regional director, called it one of the worst transboundary haze episodes to hit South-east Asia. The fires in Indonesia affected neighbouring countries, while dry weather helped the smoke persist and spread.

Singapore’s air quality shows the scale clearly. The country recorded 13 consecutive days with unhealthy PSI readings. This was its longest uninterrupted period since the 2015 haze crisis. A day counts as unhealthy when the PSI exceeds 100 at any point in any part of Singapore.

Conditions remained serious on Oct 17. The 24-hour PSI stayed in the unhealthy range, and hourly PM2.5 readings were high. Churchill expected more unhealthy days and hours. Singapore’s environment minister warned that air quality could even reach hazardous levels, while improvement might take three or four weeks.

Unhealthy PSI and PM2.5 readings mean people are breathing polluted air, so communities need to reduce exposure, especially during outdoor activities. The article highlights practical disruption rather than giving medical details. Haze can affect whether schools, sports centres and other outdoor places can operate safely.

Singapore temporarily closed all ActiveSG outdoor and non-air-conditioned sports facilities when conditions worsened. They resumed operations on Oct 17, but The Kallang’s Water Sports Centre suspended operations from 11am because visibility was weak. Regional warnings also help people decide when to protect themselves and avoid polluted conditions.

The episode shows that haze affects more than air-quality charts. It can interrupt exercise, water sports and other outdoor routines. Hourly PM2.5 readings remained high on Oct 17, while the 24-hour PSI stayed unhealthy. Further disruptions could continue until winds shift or rain puts out the fires.

El Nino is a weather phenomenon linked in this episode to hotter and drier conditions across the equatorial ASEAN region. It matters because fire control becomes harder when vegetation and land are dry, rain is limited, and flames can continue spreading. Churchill said the current event was on track to be the strongest ever observed.

The timing made the danger greater. El Nino arrived during the region’s dry season, creating what Churchill called “the perfect storm” for persistent fires. When land is cleared through slash-and-burn practices, dry conditions make escaped fires more likely to grow and harder to extinguish.

The result is prolonged smoke and haze. Churchill expected unhealthy days and hours to keep increasing. The fires may continue until winds change and rain drenches them, with monsoon rains later in the year offering a possible natural end to the episode. International assistance may help before then.

Wind determines where smoke travels, while rainfall helps extinguish the fires producing it. When winds blow from the south, haze can move toward Singapore from Indonesian fire areas. If winds become lighter and more variable, conditions may improve because less smoke is carried into the Republic.

Singapore’s Minister Grace Fu said this change was expected only in three to four weeks. A larger shift may come closer to the end of the year, when winds begin blowing from the north instead of the current southerly direction. Those winds would push haze away from Singapore.

Rain is the other major clearing mechanism. Churchill said monsoon rains later in the year should douse the fires. Until then, haze can persist or spread. The exact path and duration depend on changing winds, rainfall and whether firefighting efforts reduce the active fires sooner.

The proposed solution is regional cooperation. Fires and smoke cross borders, so countries need shared warnings, forecasts and firefighting capacity. Better information can help communities protect themselves earlier, while coordinated action can prevent fires from reaching extreme levels.

Churchill proposed that ASEAN pool firefighting resources. Members could buy equipment for shared use, exchange technical expertise and make it possible for crews from neighbouring countries to deploy quickly. He pointed to Australia’s reciprocal arrangements with New Zealand, the United States and Canada, where people and equipment can be integrated immediately.

Singapore offered Indonesia civilian assistance for firefighting and cloud seeding. Continued international support could help control current fires, but prevention also matters. Churchill said similar agricultural practices exist elsewhere in South-east Asia, so cooperation should address future risks across the region, not only this Indonesian episode.

Slash-and-burn land clearing uses fire to prepare land, according to the article. It matters because fires started during dry weather can escape control, persist and spread. When smoke crosses borders, a local land-management choice becomes a regional air-quality crisis affecting several countries.

The article links traditional clearing practices with wildfires. El Nino and the dry season create hotter, drier conditions, forming what Churchill called “the perfect storm.” Under those conditions, fires are harder to put out, and smoke can continue rising from Indonesian fire areas for weeks or months.

Reducing future haze requires changing land practices, not only fighting flames after they begin. Churchill called for ASEAN countries to develop measures that prevent extreme episodes. The article does not specify replacement techniques, but it stresses that similar agricultural practices exist elsewhere in South-east Asia, making regional prevention important.