A visible haze blankets Quezon City on September 1, 2026, as smoke from wildfires in Kalimantan, Indonesia drifts across parts of Luzon, contributing to deteriorating air quality in Metro Manila, according to the DENR-Environmental Management Bureau (EMB). Maria Tan, ABS-CBN News
MANILA — The hazy skies seen across parts of the Philippines over the past days are not caused by morning mist.
They are, instead, a result of transboundary haze—air pollution that has traveled hundreds of kilometers from massive forest fires burning in Indonesia.
The smoke, carried by the southwest monsoon winds, has caused air quality to deteriorate in Metro Manila and several provinces, prompting health warnings as fine particles in the air reach levels considered dangerous to breathe.
WHAT IS TRANSBOUNDARY HAZE
Transboundary haze is a form of air pollution that crosses national borders.
It occurs when smoke from widespread forest or peatland fires is carried by prevailing winds into neighboring countries. Unlike localized pollution from vehicle emissions or factories, transboundary haze can affect regions hundreds or even thousands of kilometers away from the source of the fires.
The haze is made up of smoke, ash, dust and microscopic particles known as PM2.5—pollutants small enough to penetrate deep into the lungs and even enter the bloodstream.
The phenomenon has affected Southeast Asia for many years, particularly during prolonged dry seasons in Indonesia. Major haze episodes have repeatedly impacted Indonesia, Malaysia, Singapore, Brunei and, during severe events, parts of the Philippines.
Metro Manila air quality reaches ‘acutely unhealthy’ levels amid haze from Indonesia
WHY IS IT HAPPENING NOW
According to Indonesia's National Disaster Mitigation Agency, widespread forest and land fires are burning in East and West Kalimantan, Riau, South Sumatra and Jambi.
The ASEAN Specialized Meteorological Centre (ASMC), which monitors haze across the region, has raised the regional alert to Level 3, indicating a high risk of severe transboundary haze due to persistent smoke from multiple fire hotspots over several days.
The ASMC also reported moderate to dense smoke plumes over parts of Borneo and said the haze has spread into the southwestern, western and central Philippines.
WHY IS THE PHILIPPINES AFFECTED
The smoke reached the Philippines because of the southwest monsoon, commonly known as Habagat.
Atmospheric scientist Dr. Gerry Bagtasa of the University of the Philippines said weather systems north of the country are helping draw the monsoon winds and the smoke they carry toward the Philippines.
He said the polluted air could linger through the end of the week if current weather patterns persist. The Department of Environment and Natural Resources' air quality monitoring stations on Tuesday, recorded Very Unhealthy to Acutely Unhealthy air quality in many parts of Metro Manila as the haze blanketed the capital.
The pollution has also spread to provinces including Cebu, Palawan, and Mindoro, where air quality readings have also reached unhealthy levels.
Environmental officials say this could become one of the worst transboundary haze episodes experienced by the country in recent years.
Indonesia forest-fire smoke reaches Philippines, may persist for days, UP scientist says
WHY IS HAZE DANGEROUS
Health experts warn that PM2.5 particles pose the greatest health risk because they are small enough to bypass the body's natural defenses.
According to infectious diseases specialist Dr. Rontgene Solante, these particles can travel deep into the lungs and may trigger coughing, worsen asthma and chronic obstructive pulmonary disease (COPD), and aggravate cardiovascular conditions.
Sensitive groups including children, older adults, pregnant women, and people with heart or lung diseases face the highest risk from prolonged exposure.
Because of the deteriorating air quality, some Filipinos have begun wearing face masks again to reduce their exposure outdoors.
Experts say the most effective long-term solution is controlling the forest fires in Indonesia.
In the short term, widespread rainfall can help clear the air by washing pollutants out of the atmosphere.
Until weather conditions change or the fires are brought under control, authorities are urging the public to monitor air quality advisories, limit outdoor activities when pollution levels are high, and wear well-fitting masks when exposure cannot be avoided.