The familiar smell of burning vegetation has returned to Singapore. As March 2026 draws to a close, residents across the island — particularly in the eastern districts — have noticed a visible deterioration in air quality, with hazy skies and the unmistakable acrid scent of smoke drifting across the Strait of Johor. The culprit, as in years past, is a combination of hotspots in the neighbouring Malaysian state of Johor and prevailing wind patterns that carry particulate matter southward into Singapore.

Data from Singapore's National Environment Agency (NEA) confirmed that PM2.5 concentrations in the eastern region reached 69 micrograms per cubic metre (ug/m3) at approximately 2am on 25 March 2026 — a level classified as unhealthy for sensitive groups and significantly above the World Health Organisation's recommended 24-hour guideline of 15 ug/m3. The term "Haze Singapore" has been trending on Google, reflecting the public's concern over what has become a recurring environmental and public health issue for both countries.

Current Air Quality Situation

The NEA has been publishing hourly updates since the onset of the current haze episode, which began in earnest around 22 March. Readings have fluctuated considerably depending on the time of day and wind direction, with PM2.5 levels ranging from a relatively benign 20 ug/m3 during periods of clearer wind to the peak of 69 ug/m3 recorded in the east.

The eastern part of Singapore has been disproportionately affected due to its proximity to the Strait of Johor and the prevailing wind corridors. Residents in areas such as Pasir Ris, Tampines, Changi, and Bedok have reported the strongest haze conditions, with visibility noticeably reduced during the early morning and late evening hours when atmospheric conditions tend to trap pollutants closer to the ground.

As of 26 March, the 24-hour Pollutant Standards Index (PSI) for Singapore remained in the moderate range for most of the island, though the eastern region has periodically touched the lower end of the unhealthy band. The NEA has advised members of the public to monitor updates via its website and the myENV mobile application, and to reduce prolonged outdoor physical exertion when readings are elevated.

Johor Hotspot Sources

Satellite imagery from the ASEAN Specialised Meteorological Centre (ASMC) has identified multiple active hotspots across Johor, concentrated in the districts of Kota Tinggi, Pontian, and Mersing. These hotspots are associated with a combination of agricultural land-clearing practices, plantation management burns, and — most critically — peatland fires that are notoriously difficult to extinguish once ignited.

Peatland fires are the primary driver of prolonged haze episodes in the region. Unlike surface vegetation fires, peat burns underground and can smoulder for weeks or even months, releasing dense plumes of smoke that contain high concentrations of fine particulate matter. Johor's extensive peatland areas, some of which have been drained for agricultural use over the past several decades, are particularly susceptible during dry spells.

Malaysia's Department of Environment (DOE) has confirmed awareness of the hotspots and stated that enforcement teams have been deployed to identify the sources. The Malaysian authorities have also noted that the current dry spell, with below-average rainfall recorded across Johor throughout March, has created conditions conducive to open burning and spontaneous peat ignition.

Cross-Border Implications

Transboundary haze remains one of the most sensitive environmental and diplomatic issues between Malaysia and Singapore. The two nations share a narrow waterway — the Strait of Johor is less than two kilometres wide at its narrowest point — meaning that even moderate burning activity in southern Johor can rapidly affect air quality across the border.

Singapore's Transboundary Haze Pollution Act 2014 gives the government legal authority to take action against entities whose activities cause or contribute to haze pollution in Singapore, even if those entities are based overseas. However, the practical enforcement of this legislation across international boundaries has proven challenging. Both countries are also signatories to the ASEAN Agreement on Transboundary Haze Pollution, ratified in 2003, though critics argue it lacks binding enforcement mechanisms.

Diplomatic communications between Putrajaya and Singapore on the current episode have been described as constructive by officials on both sides, with real-time data sharing occurring through established bilateral channels.

Health Advisory and Precautions

Health authorities in both Singapore and Johor have issued advisories urging residents to take precautions during the current haze period. The key recommendations include:

  • Reduce prolonged outdoor exertion — especially during early morning and late evening when PM2.5 levels tend to peak
  • Wear N95-rated masks — standard surgical masks do not filter fine particulate matter effectively; only N95 or equivalent masks provide adequate protection
  • Keep windows and doors closed — use air conditioning with recirculation mode where available to minimise indoor exposure
  • Use air purifiers — HEPA-filter air purifiers can significantly reduce indoor PM2.5 concentrations
  • Stay hydrated — drink plenty of water to help the body manage respiratory irritation
  • Monitor air quality readings — check the NEA or DOE websites and apps before planning outdoor activities

Particular caution is advised for vulnerable groups, including children, the elderly, pregnant women, and individuals with pre-existing respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD). The Singapore Ministry of Health has reminded general practitioners and hospital emergency departments to be prepared for an increase in respiratory-related consultations should conditions worsen.

Historical Context of Transboundary Haze

Southeast Asia has grappled with transboundary haze for decades. The 1997 crisis, triggered by massive fires in Sumatra and Kalimantan during an El Nino drought, caused an estimated USD 9 billion in economic damage. In June 2013, Singapore's PSI readings exceeded 400 — deep into the hazardous range — forcing school closures and flight cancellations. The 2015 crisis was estimated to have caused over USD 16 billion in losses across the region.

While the current Johor-originating haze is considerably less severe than those landmark episodes, it serves as a reminder that the underlying structural issues — inadequate land-use regulation, peatland degradation, and the economic incentives driving slash-and-burn agriculture — remain largely unresolved. Climate change projections suggest that drier conditions may become more frequent in the coming decades.

Economic Impact

Even moderate haze episodes carry meaningful economic consequences for both Singapore and Malaysia. The most immediate impact is on tourism — Singapore, which welcomed over 16 million visitors in 2025, depends heavily on its reputation as a clean, green city-state. Prolonged haze periods deter tourists and lead to cancellations. The aviation sector faces potential disruptions too, with Changi Airport having experienced flight delays during previous episodes when visibility dropped below operational thresholds.

Across the causeway, Johor's own economy is affected. The state's growing reputation as a destination for Singaporean tourists and property buyers is at odds with the negative publicity generated by haze events. Iskandar Malaysia, the major economic development corridor in southern Johor, has invested heavily in attracting international business — an effort undermined when air quality makes headlines for the wrong reasons.

Research published by the Singapore Institute of International Affairs estimates that a severe haze episode can cost Singapore alone between SGD 100 million and SGD 700 million, depending on duration and intensity. The broader costs across the region — healthcare expenditure, lost productivity, reduced agricultural output, and environmental degradation — are significantly higher.

What Comes Next

Meteorological forecasts suggest that the dry spell across Johor is expected to continue into early April, which could prolong haze conditions if hotspots are not brought under control. The Malaysian Meteorological Department has indicated that significant rainfall is not expected in the southern peninsula until mid-April at the earliest.

Environmental groups in both countries have renewed calls for stricter enforcement of anti-burning regulations and greater investment in peatland restoration. For residents on both sides of the strait, the practical reality remains the same: monitor the readings, take precautions when levels are elevated, and hope that the winds shift or the rains arrive. It is a familiar pattern — and one that the region continues to navigate with a mixture of pragmatism and frustration.