Asia Dominates Global Air Pollution Rankings as Health Crisis Looms

A staggering nineteen of the world’s twenty most polluted cities are in Asia, according to the latest World Air Quality Report released by Swiss air-monitoring organisation IQAir. The findings, published on Tuesday, paint a grim picture of air quality across the region, with only seven countries worldwide meeting the World Health Organisation’s (WHO) stringent PM2.5 standards in 2024. As dense smog continues to choke cities from Lahore to Byrnihat, the health implications for millions are profound, raising urgent questions about policy responses and regional cooperation.

The report, which draws on data from over 40,000 monitoring stations across 138 countries, identifies Byrnihat in Assam, India, as the most polluted city globally, with an annual PM2.5 average of 128.2 micrograms per cubic metre (µg/m³). PM2.5 particles, measuring 2.5 micrometres or less in diameter, are particularly dangerous due to their ability to penetrate deep into the lungs and bloodstream, contributing to respiratory and cardiovascular diseases and premature death. For context, the WHO recommends an annual average of no more than 5 µg/m³—a threshold that Byrnihat exceeds by over 25 times.

A Regional Crisis Unfolds

Asia’s dominance in the pollution rankings is stark. Of the top twenty most polluted cities, thirteen are in India, four in Pakistan, and one each in China and Kazakhstan. The only non-Asian city on the list is N’Djamena, the capital of Chad, which also topped the country rankings with an annual PM2.5 average of 91.8 µg/m³—18 times the WHO standard. Other heavily polluted countries include Congo, Bangladesh, Pakistan, and India, underscoring the scale of the challenge in the Global South.

In South East Asia, while no city cracked the top twenty, the situation remains dire. Thailand, often plagued by seasonal smog, ranked 29th among countries, with Chiang Mai listed as its most polluted city at 424th globally, recording an annual PM2.5 average of 91 µg/m³. This figure far exceeds Thailand’s own safe standard of 37.5 µg/m³, let alone the WHO benchmark. Images of commuters navigating smog-engulfed roads in cities like Lahore, captured as recently as December 2024, are a stark reminder of the lived reality for millions across the region.

Surprisingly, only 17% of the 8,954 cities measured worldwide met the WHO’s air quality guidelines. The seven countries that did—Australia, the Bahamas, Barbados, Estonia, Grenada, Iceland, and New Zealand—stand in sharp contrast to the majority struggling with hazardous air. For South East Asian nations like Vietnam, Indonesia, and Malaysia, where urbanisation and industrial growth often outpace environmental protections, the path to cleaner air feels increasingly elusive.

Health Impacts and Vulnerable Populations

The health consequences of prolonged exposure to PM2.5 are well-documented. According to WHO estimates, air pollution contributes to seven million premature deaths annually, with low- and middle-income countries bearing the brunt. In Asia, where dense urban populations and industrial emissions collide with seasonal factors like crop burning and weather patterns, the risks are amplified. Children, the elderly, and those with pre-existing health conditions are particularly vulnerable, facing higher rates of asthma, bronchitis, and heart disease.

In Thailand, for instance, the annual smog season in northern regions like Chiang Mai has become a public health crisis, with hospitals reporting spikes in respiratory cases during peak pollution periods. Similar patterns are observed in Vietnam’s urban centres like Hanoi and Ho Chi Minh City, where motorbike exhausts and construction dust compound the problem. Meanwhile, in Indonesia, forest fires and peatland burning—often linked to palm oil production—regularly blanket cities like Jakarta and parts of Sumatra in toxic haze, affecting not just locals but neighbouring Malaysia and Singapore.

The economic toll is equally significant. Lost productivity due to illness, coupled with rising healthcare costs, places a heavy burden on governments already grappling with development challenges. If unaddressed, the crisis could deepen inequality, as poorer communities—often living closer to industrial zones or lacking access to air purifiers—suffer disproportionately.

Policy Challenges and Regional Disparities

Addressing air pollution in Asia is a complex, multifaceted challenge. While industrial emissions and vehicular exhausts are major contributors, regional practices such as crop burning in India and Pakistan, or slash-and-burn agriculture in Indonesia, play a significant role. Transboundary pollution further complicates matters, as haze from one country often drifts into another, necessitating cooperative solutions that have, thus far, been slow to materialise.

In Thailand, efforts to curb smog in Chiang Mai and other northern areas have included temporary school closures, mask distribution, and public awareness campaigns. Yet, critics argue these are band-aid measures that fail to tackle root causes like agricultural burning and lax industrial regulations. Vietnam, meanwhile, has pledged to transition to cleaner energy sources under its National Power Development Plan, but progress remains uneven, with coal still dominating the energy mix in many South East Asian nations.

India, home to the majority of the world’s most polluted cities, faces an uphill battle. While initiatives like the National Clean Air Programme aim to reduce PM2.5 levels by 20-30% in over 100 cities by 2024, implementation has been inconsistent. In Pakistan, where cities like Lahore routinely grapple with smog so thick it disrupts daily life, government responses have often been reactive rather than preventive, with temporary lockdowns and school closures during peak pollution days.

Contrast this with the seven countries meeting WHO standards, most of which benefit from geographic isolation, smaller populations, or stringent environmental policies. For densely populated, rapidly industrialising Asia, such conditions are harder to replicate. If reforms or investments in green technology do reduce emissions, the health and economic benefits could be transformative—though experts caution that such outcomes remain speculative without sustained political will.

More than a Call for Action and More Than a Wake Up Call

The IQAir report serves as a sobering wake-up call for Asian governments and the international community. While individual countries must prioritise stricter regulations, cleaner energy, and urban planning that reduces emissions, the transboundary nature of air pollution demands regional collaboration. Frameworks like the ASEAN Agreement on Transboundary Haze Pollution, signed in 2002, offer a starting point, but enforcement remains a challenge, particularly when economic priorities clash with environmental goals.

Public awareness is also critical. In cities across South East Asia, from Bangkok to Jakarta, citizens are increasingly vocal about their right to clean air, with social media amplifying calls for accountability. Grassroots movements, alongside international pressure, could push policymakers to act more decisively, though systemic change will take time.

For now, millions continue to breathe air that shortens their lives. The stark disparity between the seven countries meeting WHO standards and the vast majority failing to do so underscores a global inequality in environmental health. As Asia grapples with this crisis, the question remains: can the region balance growth with the urgent need for cleaner skies, or will the smog persist as a deadly hallmark of progress?