Haze in Singapore is mainly caused by tiny pollutant particles in the air from both local weather conditions and regional burning activities in nearby countries.

What Causes Haze in Singapore? (Quick Scoop)

1. The Two Big Reasons

A. Transboundary haze from regional fires

This is the classic “haze season” that many people in Singapore know:

  • Forest and peatland fires in Indonesia (especially Sumatra and Kalimantan) produce thick smoke that can travel across borders.
  • These fires are often linked to:
    • Slash-and-burn land clearing for agriculture (e.g. palm oil, timber)
* Wildfires on very flammable drained peatlands during the dry season
  • When regional winds blow from the southwest or west during dry periods, that smoke gets pushed towards Singapore, leading to several days or weeks of bad air.

In short: someone is burning somewhere in the region, and the wind carries it here.

B. Local haze from weather + pollutants

Not every hazy day is due to Indonesian fires. Sometimes the sky looks milky or “foggy” even without regional smoke:

  • Light or weak winds can cause particulate matter (PM2.5 and PM10) to accumulate over Singapore instead of being dispersed.
  • These particles come from local sources such as vehicle exhaust, industry, small fires, and general urban pollution.
  • When air is still and humid, visibility drops and the sky looks hazy, even if PSI is only in the “moderate” range.

Example: In March 2025, hazy conditions were attributed to an accumulation of particulate matter under light wind conditions , not to transboundary smoke.

2. Recent Cases & “Latest News” Angle

  • In January 2026, haze in eastern Singapore was linked to a hotspot and smoke plume from Johor, Malaysia, with slightly elevated PM2.5 and a faint burning smell.
  • Authorities noted that haze can occur whenever two things line up:
    1. There are fires producing smoke in the region
    2. Wind direction happens to blow that smoke towards Singapore

So the latest pattern : even “small” localized vegetation fires in Malaysia or Indonesia can briefly push haze into Singapore when the wind cooperates.

3. How Weather Makes It Worse (or Better)

Key weather factors that influence haze in Singapore:

  • Dry seasons : Less rain to wash particles out of the air, higher risk of fires in the region.
  • Wind direction :
    • Southwest/west winds can carry smoke from Sumatra
    • North/northeast winds can carry smoke from peninsular Malaysia or nearby hotspots
  • Wind speed :
    • Light winds → particles “sit” over Singapore, haze builds up
* Stronger winds → better dispersion, haze clears faster

Think of it like this: fires create the smoke, but the wind decides whether Singapore has to breathe it.

4. What Exactly Is in the Haze?

Haze is mostly made up of particulate matter and other pollutants:

  • PM2.5 : very fine particles (less than 2.5 micrometres) that can enter deep into the lungs and bloodstream; these are the dominant pollutant during haze episodes.
  • PM10 : larger but still inhalable particles.
  • Other gases in the air quality index include sulphur dioxide, nitrogen dioxide, ozone, and carbon monoxide.

Singapore tracks this with the Pollutant Standards Index (PSI) , where readings above 101 are considered unhealthy.

5. How Forums and Public Talk Frame It

If you browse local forums and chats, you’ll usually see a few recurring viewpoints (and arguments):

  1. “It’s Indonesia’s slash-and-burn again.”
    • People point to satellite images and news on peat/forest fires and blame agricultural practices.
  1. “Not all haze is ‘Indo haze’.”
    • Others note days when PSI is moderate but the sky still looks hazy and say it’s due to local pollution and weather trapping particles.
  1. “Climate change is making it worse.”
    • Some discussions link more intense/longer dry spells and more frequent fires to a warming climate, making haze episodes more common or unpredictable.
  1. “It’s just another seasonal thing we live with.”
    • Especially after multiple years of repeated episodes, some treat it as an annual or semi-regular event tied to regional dry seasons.

You’ll also see people sharing screenshots of PSI/PM2.5 readings, NEA maps, and debating whether what they see outside is “real haze” or just humidity plus pollution.

6. Side Note: Health & Daily Life (Brief)

Even though you asked about causes, the impact is a big part of the conversation:

  • Haze episodes can irritate the eyes and throat, worsen asthma and heart/lung conditions, and affect outdoor activities.
  • Government advisories usually kick in once PSI rises, with recommendations like limiting strenuous outdoor activity and wearing suitable masks.

This is why each “haze wave” quickly becomes a trending topic—people want to know: what’s causing it this time, and how bad will it get?

7. TL;DR (Quick Answer)

  • Main cause : Smoke from forest, peatland and agricultural fires in nearby countries (especially Indonesia and sometimes Malaysia), carried over by regional winds.
  • Other cause : Local build-up of particulate matter under light winds and certain weather conditions, even without major regional fires.
  • Key trigger combo : Someone burning biomass in the region + wind blowing the smoke towards Singapore + dry conditions that prevent dispersion.

Information gathered from public forums or data available on the internet and portrayed here.