Singapore Haze: Can a Transboundary Pollution Law Work?
Singapore says it is identifying companies behind Indonesian peatland fires and may act under its Transboundary Haze Pollution Act, testing how far national law can reach across borders.
Singapore Prime Minister Lawrence Wong said on 15 October 2026 that the city-state is identifying companies behind the Indonesian forest and peatland fires driving this year's haze. Singapore may act under its Transboundary Haze Pollution Act and explore joint action with other countries. Its 24-hour Pollution Standards Index (PSI) has stayed in the unhealthy range since 5 October.
Can Singapore punish companies for fires in Indonesia?
In law, yes. Singapore's Transboundary Haze Pollution Act of 2014 covers conduct outside Singapore that causes haze inside it, with fines up to S$100,000 a day, capped at S$2 million. In practice it needs evidence of which company's land burned, so Prime Minister Lawrence Wong has also said Singapore will explore joint action with other countries.
Where warranted, we will take action under Singapore's Transboundary Haze Pollution Act, and explore joint action with other countries.
Lawrence Wong, Prime Minister of Singapore, social media post (15 October 2026)
What Happened?
Singapore's air has been in the unhealthy PSI range since 5 October 2026. As of 10 am on 13 October, the 24-hour PSI read 172 in the west and 170 in central Singapore, and local reports put the year's peak at 192 in the central region on 9 October. On 15 October, Prime Minister Lawrence Wong said Singapore is looking into which companies may be responsible for the fires in Indonesia and may use the Transboundary Haze Pollution Act, alongside joint action with other countries.
The Act was passed in 2014 and applies once the 24-hour PSI reaches the unhealthy range for a sustained period, covering conduct inside or outside Singapore. Penalties reach S$100,000 for each day of haze, up to S$2 million. Singapore's National Environment Agency has said investigations that began after the 2015 haze into Indonesian companies remain open.
Why It Matters
The haze tests whether a national law can discipline polluters beyond its borders. Singapore has the legal tool but lacks access to the burned land, so it depends on Indonesian cooperation and on satellite and corporate-ownership evidence. The fires themselves are cheap land-clearing for plantations, and peat burns for weeks once lit. For India, the lesson is direct: when pollution crosses an administrative boundary, enforcement fails unless the polluter can be identified and the neighbouring authority cooperates. Delhi's winter smog and stubble burning in neighbouring states follow the same pattern.
Concept Behind the News: Transboundary Pollution
International law holds that a state must not let its territory be used to cause serious harm to another. The Trail Smelter arbitration (1941) set the precedent, and Principle 21 of the Stockholm Declaration (1972) and Principle 2 of the Rio Declaration (1992) repeat it. The ASEAN Agreement on Transboundary Haze Pollution was signed in 2002 and sets up regional monitoring through the ASEAN Specialised Meteorological Centre in Singapore. Peatland is carbon-rich waterlogged soil; drained peat burns easily and smoulders underground, releasing large volumes of particulate matter. Singapore measures air with the PSI: 0 to 50 is good, 51 to 100 moderate, and 101 to 200 unhealthy. India uses the Air Quality Index and its own National Ambient Air Quality Standards.
Syllabus Connection
- GS-III (Environment): Pollution, air quality standards and climate change
- GS-III (Environment): International conventions and environmental law principles
- GS-II (IR): ASEAN and regional groupings
- GS-III (Environment): Polluter pays and precautionary principles in Indian law
PYQ Connection
UPSC Prelims 2022
Question: In the context of WHO Air Quality Guidelines, consider the following statements: 1. The 24-hour mean of PM2.5 should not exceed 15 μg/m³ and annual mean of PM2.5 should not exceed 5 μg/m³. 2. In a year, the highest levels of ozone pollution occur during the periods of inclement weather. 3. PM10 can penetrate the lung barrier and enter the bloodstream. 4. Excessive ozone in the air can trigger asthma. Which of the statements given above are correct?
- 1, 3 and 4
- 1 and 4 only
- 2, 3 and 4
- 1 and 2 only
Answer: 1 and 4 only
Option (b) is correct. The 2021 WHO guideline values are 15 μg/m³ for the 24-hour PM2.5 mean and 5 μg/m³ for the annual mean, and excess ozone can trigger asthma. Statement 2 is wrong because ozone peaks in sunny, warm weather. Statement 3 is wrong because it is the finer PM2.5 that reaches the bloodstream. Haze from peat fires is dominated by PM2.5.
UPSC Prelims 2016
Question: In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index? 1. Carbon dioxide 2. Carbon monoxide 3. Nitrogen dioxide 4. Sulfur dioxide 5. Methane Select the correct answer using the code given below.
- 1, 2 and 3 only
- 2, 3 and 4 only
- 1, 4 and 5 only
- 1, 2, 3, 4 and 5
Answer: 2, 3 and 4 only
Option (b) is correct. India's AQI covers carbon monoxide, nitrogen dioxide and sulphur dioxide, along with particulates and ozone, ammonia and lead. Carbon dioxide and methane are greenhouse gases and are not part of the AQI. Singapore's PSI works on a similar pollutant basket.
UPSC Prelims 2024
Question: One of the following regions has the world's largest tropical peatland, which holds about three years worth of global carbon emissions from fossil fuels; and the possible destruction of which can exert detrimental effect on the global climate. Which one of the following denotes that region?
- Amazon Basin
- Congo Basin
- Kikori Basin
- Rio de la Plata Basin
Answer: Congo Basin
Option (b) is correct. The Cuvette Centrale peatland in the Congo Basin is the largest tropical peatland. Southeast Asian peatlands in Indonesia are the other major tropical store, and their burning is what causes the haze seen in Singapore.
CAPF 2023
Question: 'Basel Convention', 'Rotterdam Convention' and 'Stockholm Convention' relate to which of the following?
- Human Rights of Prisoners
- Management of Pollutants
- Conservation of Wetlands
- Conservation of Rivers
Answer: Management of Pollutants
Option (b) is correct. These three conventions govern hazardous wastes, hazardous chemicals and persistent organic pollutants. Do not confuse the Stockholm Convention (2001, on pollutants) with the Stockholm Declaration (1972), which first stated that states must not cause environmental harm to others.
CDS 2023
Question: Which of the following statements about ASEAN are correct? 1. The Chairmanship of ASEAN rotates annually based on the alphabetical order of the English names of Member States. 2. The Chairmanship is decided by voting among the Member States. 3. "One Vision, One Identity, One Community" is the ASEAN motto. 4. 12th August is celebrated as ASEAN Day. Select the correct answer using the code given below:
- 1 and 2 only
- 1 and 3 only
- 3 and 4 only
- 1, 2, 3 and 4
Answer: 1 and 3 only
Option (b) is correct. The chair rotates alphabetically and the motto is "One Vision, One Identity, One Community". The chair is not decided by vote, and ASEAN Day is 8 August, not 12 August. The ASEAN haze agreement works within this consensus-based, non-binding style.
UPPSC 2025
Question: With reference to 'Delhi Government's Bio-decomposer and Spray Programme', which of the following statements is/are correct? 1. The Bio-decomposer solution is provided free of cost to farmers to help convert stubble into manure. 2. The Bio-decomposer solution is prepared using a mix of several fungi.
- Only 2
- Both 1 and 2
- Neither 1 nor 2
- Only 1
Answer: Both 1 and 2
Both statements are correct. The bio-decomposer is a fungal solution sprayed on fields to turn paddy stubble into manure, and Delhi supplies it to farmers free. It is India's answer to crop-residue burning, the domestic cousin of Indonesia's fire-driven haze.
Visual Explanation: Singapore PSI Against the Unhealthy Threshold
Singapore 24-hour PSI readings, October 2026
| Central, 9 Oct (peak) | 192 |
|---|---|
| West, 13 Oct | 172 |
| Central, 13 Oct | 170 |
Connect the Dots
- 1941: The Trail Smelter arbitration establishes that a state must not allow its territory to harm another.
- 1972: Stockholm Declaration Principle 21 makes this a principle of international environmental law.
- 2002: ASEAN members sign the Agreement on Transboundary Haze Pollution.
- 2014: Singapore enacts the Transboundary Haze Pollution Act; Indonesia ratifies the ASEAN agreement.
- 2015: A severe haze triggers NEA investigations into Indonesian companies, some of which remain open.
- 5 October 2026: Singapore's PSI enters the unhealthy range and stays there.
- 15 October 2026: PM Wong says Singapore may act under the Act and explore joint action.
- Next: Evidence on which concessions burned, Indonesian cooperation, and ASEAN-level action.
Read More
- WHO: Ambient (outdoor) air quality and health (Health effects and guideline values for particulate matter)
- Delhi Pollution Plan: Winter Action Strategy (Previous DORI article on India's own cross-boundary smog problem)
Exam Takeaway
- Singapore's PSI has been unhealthy (above 100) since 5 October 2026; the year's peak was 192 on 9 October.
- Transboundary Haze Pollution Act, 2014: reaches conduct outside Singapore; up to S$100,000 a day, capped at S$2 million.
- ASEAN Agreement on Transboundary Haze Pollution: signed 2002; Indonesia ratified in 2014.
- Trail Smelter (1941) and Stockholm Principle 21 (1972) underpin state responsibility for transboundary harm.
- India has no transboundary air pollution statute; the Air Act, 1981 and the Environment Protection Act, 1986 govern domestic pollution.
Exam Angle
Prelims can test the polluter pays principle, air quality indices and ASEAN-level agreements as factual recall. Mains can ask: "Can national laws effectively regulate transboundary pollution, and what lessons does the Southeast Asian haze offer India?" Use the Singapore Act, the ASEAN agreement, the evidence problem and the Delhi smog parallel as your examples.
Possible Question
Practice Question
Question: With reference to transboundary pollution, consider the following statements: 1. The Trail Smelter arbitration established that a state must not allow its territory to be used in a way that harms another state. 2. Singapore's Transboundary Haze Pollution Act applies only to conduct within Singapore. 3. The polluter pays principle has been applied by the Supreme Court of India in environmental cases. Which of the statements given above is/are correct?
- 1 only
- 1 and 3 only
- 2 and 3 only
- 1, 2 and 3
Answer: 1 and 3 only
Statements 1 and 3 are correct. Trail Smelter (1941) set the state-responsibility principle, and the Supreme Court applied polluter pays in Indian Council for Enviro-Legal Action v. Union of India (1996). Statement 2 is wrong: the Act expressly covers conduct outside Singapore that causes haze there.