Three Philippine cities rank among the least polluted in Southeast Asia.

Three cities in the Philippines — Calamba, Carmona, and Balanga — ranked among the least air polluted urban areas in Southeast Asia in 2023, according to IQAir’s World Air Quality Report. That might sound like good news, and in relative terms it is. But the same report shows the country as a whole still breathes air nearly three times dirtier than the international safety guideline, which means these cities are cleaner than most of their neighbours without being truly clean by global standards.

To put those numbers in context, the World Health Organization recommends an annual average PM2.5 concentration of no more than 5 micrograms per cubic metre. Calamba’s 8.2 μg/m³ is the lowest in the Philippines, yet it still exceeds that guideline by more than 60 percent. The national average of 13.5 μg/m³ is nearly triple the safe threshold. That gap between the country’s best-performing cities and the overall picture is worth examining closely, especially if you live in or near one of these urban centres and wonder how your local air quality compares to the rest of the region. For a broader look at how pollution affects communities across the archipelago, you can read about pollution’s unequal impact on Filipino communities.

What the IQAir rankings actually tell us about Philippine air quality

The IQAir report draws on PM2.5 data from 7,812 cities across 134 countries. PM2.5 refers to fine particulate matter up to 2.5 microns in diameter — small enough to enter the bloodstream through the lungs and linked to respiratory and cardiovascular illness. The three Philippine cities that made the regional list — Calamba in Laguna, Carmona in Cavite, and Balanga in Bataan — all sit in provinces near Metro Manila, which suggests that proximity to the capital does not automatically mean poor air quality. But none of them met the WHO annual guideline of 5 μg/m³. For comparison, the cleanest city in the region was Mamuju, Indonesia, at 3.7 μg/m³, followed by Kupang, Indonesia at 4.6 μg/m³ and Bongawan, Malaysia at 6.7 μg/m³.

At the other end of the spectrum, the most polluted city in Southeast Asia was South Tangerang, Indonesia, with an average PM2.5 of 71.7 μg/m³ — more than 14 times the WHO guideline. Tay Ho, Vietnam followed at 61.5 μg/m³, and Tangerang, Indonesia at 54.1 μg/m³. The Philippines as a whole ranked 8th out of nine Southeast Asian countries, ahead of only one unnamed neighbour. That regional standing is a reminder that while a few cities perform relatively well, the national picture remains concerning.

Why the gap between top cities and national average matters

The difference between Calamba’s 8.2 μg/m³ and the national average of 13.5 μg/m³ is not trivial. It suggests that air quality varies significantly depending on where you live, and that the country’s worst-polluted areas pull the average up sharply. The report does not name the most polluted Philippine cities, but the national figure implies that many urban and industrial centres likely exceed 20 or even 30 μg/m³. That kind of variation matters for public health because prolonged exposure to PM2.5 above 10 μg/m³ is associated with increased rates of asthma, lung disease, and premature mortality.

Another factor worth noting is that the Philippines recorded a 10 percent year-on-year improvement from 2022 to 2023 — from 14.9 μg/m³ down to 13.5 μg/m³. That is a meaningful drop, but it still leaves the country far from the WHO guideline. Only seven countries worldwide met the 5 μg/m³ standard: Australia, Estonia, Finland, Grenada, Iceland, Mauritius, and New Zealand. Three territories — Puerto Rico, Bermuda, and French Polynesia — also recorded safe levels, with French Polynesia posting the cleanest air globally at 3.2 μg/m³. The Philippines has a long way to go before it joins that group, but the improvement shows that policy changes, fuel standards, or economic shifts can move the needle. For more on how local efforts are tackling pollution at the community level, see local solutions to pollution in rural PH.

What gets overlooked when we focus on city rankings

It is easy to celebrate a top-10 regional ranking, but the IQAir data contains several nuances that complicate the story. Understanding them helps avoid drawing the wrong conclusions about air quality in the Philippines.

The WHO guideline is a health-based threshold, not a regional benchmark

The 5 μg/m³ annual average is not an arbitrary target — it is the concentration below which health risks from PM2.5 are considered minimal based on current evidence. Every Philippine city on the list exceeds that level. Calamba’s 8.2 μg/m³ is 64 percent above the guideline. Carmona’s 8.9 μg/m³ is 78 percent above. Balanga’s 9.2 μg/m³ is 84 percent above. Being the least polluted in the country does not mean the air is safe; it means the air is less harmful than elsewhere.

PM2.5 is only one measure of air quality

The report uses PM2.5 as its standard indicator, but other pollutants — ground-level ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide — also affect health and are not captured here. A city could have relatively low PM2.5 but high ozone levels, especially during hot afternoons. The rankings should not be read as a complete air quality report card.

Data coverage varies by city

IQAir aggregates data from government monitors and low-cost sensors. Not every city has the same number of monitoring stations or the same quality of equipment. A city with fewer monitors may produce less representative data. The report does not specify how many stations each Philippine city used, so the figures should be treated as estimates rather than precise measurements.

Seasonal and geographic factors play a role

Calamba, Carmona, and Balanga are all located near bodies of water or in areas with regular wind patterns that can disperse pollutants. That does not mean their air quality is the result of deliberate policy — geography and meteorology may be doing much of the work. Cities in inland valleys or industrial zones face different dispersion conditions and cannot simply replicate these numbers through the same measures.

To see how these pollution patterns compare across different environmental issues, the table below summarises the key data points from the report alongside related concerns.

→ Scroll right to see all columns

What you can do with this information

Knowing your local PM2.5 level is useful only if it leads to action. Here is what the data means for different situations and how to respond.

Check real-time air quality where you live

The IQAir report provides annual averages, but air quality changes day to day and even hour to hour. You can check live PM2.5 readings through the IQAir website or mobile app, which pulls data from government stations and community sensors. If you live in or near Calamba, Carmona, or Balanga, your baseline is better than most of the country, but spikes can still occur during dry season, after volcanic activity, or near major roads. On days when PM2.5 exceeds 25 μg/m³, consider limiting outdoor exertion, especially if you have asthma or a heart condition.

Understand the limits of city-level rankings

A city ranking does not tell you about neighbourhood-level variation. A home next to a busy highway or an industrial facility may have significantly worse air than the city average. If you are choosing where to live or send your children to school, look for local monitoring data rather than relying on the city-wide figure. The same logic applies to workplaces — indoor air quality can be worse than outdoor levels in buildings with poor ventilation.

Support local monitoring efforts

One reason the Philippines has limited air quality data is the shortage of monitoring stations. Community-led projects that install low-cost sensors can fill gaps and provide more granular information. If your barangay or city council is considering an air quality monitoring programme, it is worth supporting. Better data leads to better policy and more informed personal decisions. For a deeper look at how pollution affects health outcomes across the country, read about pollution’s hidden health costs for Filipinos.

Watch for future policy changes

The 10 percent improvement from 2022 to 2023 suggests that national trends can shift. The government has discussed stricter vehicle emission standards and cleaner fuel mandates, but implementation has been uneven. If you follow environmental news, pay attention to the Department of Environment and Natural Resources (DENR) updates on air quality standards. A move toward adopting the WHO guideline as a domestic target would signal a serious commitment to public health.

Frequently asked questions about Philippine air quality rankings

Closing

The IQAir report offers a useful snapshot, but it is only one piece of a larger puzzle. Calamba, Carmona, and Balanga deserve credit for ranking well regionally, but the national average tells a more sobering story. The real measure of progress will be whether the Philippines can bring its overall PM2.5 down toward the WHO guideline — not just whether a few cities outperform their neighbours. If this was useful, you might also want to read the Philippines air index shows high pollution levels.

Sources

Pollution’s unequal impact on Filipino communities — Explores how air and water pollution disproportionately affect low-income and rural populations in the Philippines.

Local solutions to pollution in rural PH — Highlights community-driven initiatives that address pollution at the barangay level.

Three PH cities among least polluted regional cities in Southeast Asia. Inquirer.net, 2024.