Every year, Indonesia's dry season can bring a familiar environmental problem: haze.
The gray layer of smoke can cover cities, reduce visibility, disrupt transportation and push air-quality measurements into unhealthy ranges. In severe years, the effects can extend beyond Indonesia, reaching neighboring countries in Southeast Asia.
But haze is more than something people can see in the sky.
It is an air-pollution problem involving fine particles, gases and other pollutants released when vegetation, forests and especially peatlands burn.
Understanding Indonesian haze therefore requires looking beyond the fire itself. The problem is part of the wider impacts of Indonesia's wildfires, which extend beyond air pollution to include peatland degradation, biodiversity loss, public health risks and regional environmental challenges.
The important question is:
What happens to the air after a landscape starts burning?
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| Jakarta, Indonesia Photo by David Kristianto on Unsplash |
What Is Indonesia Haze?
Indonesia haze refers to widespread atmospheric pollution caused largely by smoke from fires, including forest, land and peat fires.
The smoke can contain a complex mixture of pollutants.
One of the most important is fine particulate matter known as PM2.5.
These particles are small enough to penetrate deep into the respiratory system. During major fire episodes, PM2.5 can become one of the most important indicators of health risk.
Other pollutants may include carbon monoxide and various gases and compounds produced through combustion.
The exact composition depends on what is burning, how efficiently it burns and atmospheric conditions.
This means haze is not simply "smoke."
It is a complex form of air pollution.
Why Do Forest Fires Create Haze?
When vegetation burns, combustion releases particles and gases into the atmosphere.
Under ideal conditions, combustion can be relatively efficient.
But wildfire conditions are rarely ideal.
Moist vegetation, smoldering organic material and peat can burn incompletely. Incomplete combustion can produce substantial amounts of smoke and fine particles.
Peat fires are particularly important because peat contains large quantities of organic material.
When dry peat smolders, it can produce persistent smoke even when large flames are no longer visible.
This helps explain why haze can remain severe long after a fire appears to have lost its intensity.
Why Peat Fires Are Especially Important
Indonesia's peatlands are a major part of the country's haze problem.
Healthy peatlands are naturally wet.
When peatlands are drained, however, the water table can fall and the peat becomes increasingly vulnerable to fire.
Once ignited, peat can burn underground.
That creates several problems at once:
- fires can be difficult to detect
- combustion can continue for long periods
- large quantities of smoke can be produced
- fires can reignite
- carbon stored in peat can be released
The relationship between peatlands and haze is therefore one of the most important environmental links in Indonesia.
Our related article Why Indonesia's Peatlands Keep Burning explores this process in greater depth.
What Is PM2.5?
PM2.5 refers to particulate matter with a diameter of 2.5 micrometers or smaller.
To put that into perspective, these particles are extremely small compared with the width of a human hair.
Their size is important because they can travel deep into the lungs.
According to the World Health Organization, exposure to particulate matter is associated with cardiovascular and respiratory health effects.
This is why a smoky day is not merely an inconvenience.
Poor air quality can become a public-health issue.
Why Haze Can Be More Dangerous Than It Looks
Human perception is not a reliable air-quality monitor.
The sky may look relatively clear while particulate concentrations remain elevated.
Conversely, visible haze can vary depending on humidity, sunlight and atmospheric conditions.
For this reason, people should pay attention to measured air-quality data, not simply whether smoke is visible.
Air-quality monitoring systems can provide information about pollutants such as PM2.5 and help communities understand whether conditions are safe.
This is especially important for vulnerable groups.
Who Is Most Vulnerable to Haze?
Not everyone responds to air pollution in exactly the same way.
Groups that may be particularly vulnerable include:
- children
- older adults
- pregnant people
- people with existing respiratory conditions
- people with cardiovascular conditions
- outdoor workers
- people who spend long periods outdoors
During severe haze episodes, reducing unnecessary exposure becomes particularly important.
For outdoor workers, however, avoiding exposure can be difficult.
This makes workplace protection an important part of the broader haze response.
What Happens to the Human Body During Heavy Haze?
Fine particles can enter the respiratory system and trigger irritation and inflammation.
People exposed to polluted air may experience symptoms such as:
- coughing
- throat irritation
- eye irritation
- breathing discomfort
- headaches
- worsening of existing respiratory symptoms
More serious and prolonged exposure is associated with broader health risks.
The effects also depend on pollutant concentration, duration of exposure, individual vulnerability and other factors.
This is why a single air-quality reading should not be interpreted as a complete description of someone's health risk.
Why Children Need Special Protection
Children breathe more air relative to their body size and their lungs are still developing.
Schools may therefore face difficult decisions during severe haze.
When air quality becomes hazardous, outdoor activities can be reduced or canceled, and in particularly severe situations educational activities may be disrupted.
This creates a secondary social cost of wildfire smoke.
A fire that begins hundreds of kilometers away can eventually affect:
schools → families → businesses → transportation → healthcare systems.
Haze therefore becomes more than an environmental problem.
It becomes a social and economic problem.
How Weather Controls the Movement of Haze
A wildfire does not automatically create regional haze.
Atmospheric conditions determine where smoke travels and how long it remains concentrated.
Important factors include:
- wind direction
- wind speed
- rainfall
- humidity
- atmospheric stability
- temperature
- topography
When winds carry smoke toward populated areas, air quality can deteriorate rapidly.
Rain can help remove particles from the atmosphere, although it does not necessarily extinguish every underlying fire.
This is especially important for peat fires.
Why Haze Can Cross National Borders
Smoke does not recognize political boundaries.
If fires occur in Indonesia and atmospheric winds carry the resulting pollution toward neighboring countries, haze can affect Malaysia, Singapore, Brunei and other parts of Southeast Asia.
This creates what is commonly called transboundary haze.
The issue has therefore become a regional environmental and diplomatic concern.
A fire may begin as a local land-management problem but develop into an international air-quality problem.
Indonesia Haze and Southeast Asia
The transboundary nature of haze explains why Indonesian fires have repeatedly attracted regional attention.
Countries affected by smoke may experience:
- degraded air quality
- reduced visibility
- health concerns
- school disruptions
- transportation problems
- aviation impacts
- economic losses
The situation can also create diplomatic pressure because neighboring countries may demand stronger action to prevent recurring haze.
This makes wildfire prevention part of Indonesia's regional environmental responsibility as well as a domestic issue.
Why 2026 Has Become a Major Warning
The 2026 fire season has demonstrated how quickly Indonesia's wildfire problem can escalate when dry conditions, vulnerable landscapes and ignition sources come together.
By October 2026, Indonesian authorities had deployed large numbers of personnel and aircraft to fight fires across multiple regions. Official hotspot counts have also fluctuated substantially from day to day, showing why a single hotspot number should not be treated as a measure of total burned area.
Recent reporting has described severe haze across parts of Indonesia and neighboring Southeast Asian countries.
The situation has included health concerns, school disruptions and significant firefighting operations.
However, different agencies and independent researchers have produced different estimates of burned area.
That distinction matters.
Hotspots, fire incidents, burned area and air-quality measurements are not the same thing.
They measure different aspects of the crisis.
Hotspots Do Not Equal Fires
Satellite hotspot data are extremely useful for monitoring fire activity.
But a hotspot is not automatically a confirmed wildfire.
Satellite systems detect thermal anomalies, and those anomalies can have different causes.
Therefore:
Hotspot count ≠ number of fires ≠ burned area.
A location can also remain thermally active without representing a large fire.
Conversely, some fires may be difficult to detect because of cloud cover, timing or other technical limitations.
This is why credible wildfire analysis combines satellite observations with ground verification and other data.
How Air Quality Is Measured
Air quality can be communicated through different systems, including air-quality indices and pollutant concentration measurements.
One of the most widely discussed pollutants during Indonesian haze is PM2.5.
Monitoring stations can measure concentrations over time, allowing authorities and the public to track changes.
Satellite observations can complement ground-based measurements by providing a broader geographic picture.
Together, these technologies can help answer different questions:
Ground stations:
How polluted is the air at this location?
Satellites:
Where are smoke and fire activity occurring across a large area?
Weather models:
Where might the smoke travel?
The combination provides a much more useful picture than any single dataset.
What Should People Do During Severe Haze?
When air quality deteriorates, exposure reduction becomes important.
Practical measures can include:
Check air-quality information
Do not rely only on what the sky looks like.
Reduce unnecessary outdoor activity
Especially when pollution reaches unhealthy levels.
Improve indoor air quality
Keeping windows and doors closed during severe outdoor pollution may reduce indoor exposure, depending on building conditions.
Avoid adding indoor pollution
Smoking and other sources of indoor particulate pollution can further degrade air quality.
Use appropriate respiratory protection
Well-fitting particulate-filtering masks can reduce inhalation of fine particles when used correctly.
Pay attention to vulnerable people
Children, older adults and people with existing health conditions may need additional protection.
These measures do not solve the fire problem.
They reduce exposure while the larger environmental emergency is being addressed.
What Can Governments Do?
Long-term haze reduction requires action before fires become major disasters.
Important strategies include:
- protecting peatlands
- maintaining appropriate peat water levels
- improving fire detection
- strengthening local firefighting capacity
- enforcing restrictions on illegal burning
- improving land-use planning
- investigating corporate and individual responsibility
- supporting sustainable livelihoods
- coordinating across provinces
- strengthening regional cooperation
Emergency firefighting remains necessary.
But firefighting alone cannot solve recurring haze.
If the underlying landscape remains highly flammable, the cycle can repeat.
What Can Companies Do?
Companies operating in fire-prone landscapes have an important role.
Responsible land management can include:
- maintaining firebreaks
- monitoring concession areas
- preventing illegal burning
- maintaining water-management systems
- preparing emergency response teams
- monitoring high-risk areas
- investigating fires quickly
- cooperating with authorities
Corporate responsibility should not be reduced to responding after a fire begins.
Prevention is the more important test.
Why Indonesia's Haze Problem Is Also a Land-Use Problem
It is tempting to describe haze simply as a natural disaster.
But many major fires occur within landscapes shaped by human decisions.
Drainage systems, plantations, agricultural expansion, road development, land clearing and settlement patterns can all influence fire vulnerability.
This means the haze problem sits at the intersection of:
environment + agriculture + economics + governance + public health.
That is why solving it requires more than environmental agencies.
The Economic Cost of Haze
Haze can impose costs far beyond firefighting.
Businesses can be affected by:
- employee illness
- reduced productivity
- transportation disruption
- flight delays
- tourism losses
- school closures
- supply-chain interruptions
Healthcare systems may also face additional demand during severe pollution episodes.
These indirect costs can be difficult to calculate because they extend across many sectors.
But they demonstrate an important principle:
Preventing fire can be economically cheaper than managing its consequences.
Why Prevention Must Start Before the Fire Season
By the time thick smoke covers a city, many of the most important prevention opportunities have already passed.
Effective fire management should begin during the wetter months.
Authorities and land managers can use this period to:
- restore water levels
- maintain canals and infrastructure
- inspect high-risk landscapes
- prepare firefighting equipment
- train local teams
- map vulnerable areas
- monitor land clearing
- establish early-warning systems
Preparation determines how quickly a fire can be contained.
The Future of Indonesia's Haze
Indonesia's haze problem is unlikely to disappear through a single policy.
It requires a combination of:
better land management + healthy peatlands + early detection + enforcement + community participation + regional cooperation.
Climate variability adds another layer of uncertainty.
During unusually dry periods, landscapes that have already been degraded can become much more dangerous.
That means climate adaptation and fire prevention increasingly need to be treated as connected issues.
The Bigger Lesson
Indonesia's haze crisis shows how environmental problems move through systems.
A fire begins in a landscape.
The smoke enters the atmosphere.
Pollution reaches communities.
People experience health effects.
Schools and businesses are disrupted.
Smoke crosses borders.
A local fire becomes a regional issue.
That chain is what makes haze such an important environmental story.
The solution therefore cannot stop at extinguishing flames.
Indonesia needs to reduce the conditions that allow landscapes to burn in the first place.
Because the clearest sky is not created by fighting smoke.
It is created by preventing the fire that produces it.