Air pollution is one of the gravest environmental challenges of the 21st century. According to global air quality monitoring organisations, only a small fraction of cities meet World Health Organisation (WHO) air quality standards, and millions are breathing air that poses severe health risks.
Air pollution is typically assessed using the Air Quality Index (AQI) - a scale that reflects concentrations of harmful pollutants such as PM2.5 (fine particulate matter), PM10, NO₂, SO₂, and ozone. PM2.5 is especially dangerous because these microscopic particles penetrate deep into the lungs and bloodstream.
Based on recent IQAir AQI rankings (2025)- one of the most referenced global air quality data sources - here are the cities with the worst air quality in the world today:
|
Rank |
City |
Country/Region |
AQI (US) |
|
1 |
Delhi |
India |
190+ |
|
2 |
Baghdad |
Iraq |
180 |
|
3 |
Kolkata |
India |
170 |
|
4 |
Dhaka |
Bangladesh |
162 |
|
5 |
Lahore |
Pakistan |
160 |
|
6 |
Manama |
Bahrain |
158 |
|
7 |
kampala |
Uganda |
158 |
|
8 |
Doha |
Qatar |
157 |
|
9 |
Karachi |
Pakistan |
157 |
|
10 |
Mumbai |
India |
152 |
The table above represents a daily global AQI snapshot, not an annual pollution ranking. On the observed day in December 2025, Delhi recorded the worst air quality in the world, surpassing all other monitored cities in terms of US AQI levels. This distinction is critical. Air quality rankings can change daily due to weather patterns, emissions, and regional activities, but such snapshots reveal where pollution becomes acutely dangerous in real time.
What stands out immediately is the regional concentration of polluted cities. South Asia and the Middle East dominate the list, indicating that air pollution is not an isolated urban problem but a regional and structural crisis shaped by shared economic models, energy dependence, and environmental governance gaps.
City-Level Context: Why These Cities Rank So High
Delhi, India (Rank 1 | AQI ~190+)
Delhi’s position at the top reflects a convergence of multiple pollution sources. Vehicular emissions, coal-based power generation, construction dust, and winter temperature inversion trap pollutants close to the ground. Seasonal agricultural burning in surrounding states further intensifies the crisis. On days like this, Delhi’s air enters the “Very Unhealthy” to “Hazardous” category, posing immediate health risks even to healthy individuals.
Baghdad, Iraq (Rank 2 | AQI ~180)
Baghdad’s pollution stems from oil-based energy systems, diesel generators, industrial activity, and frequent dust storms. Years of infrastructure damage and limited environmental regulation have created conditions where pollution persists regardless of season, making high AQI days increasingly common.
Kolkata, India (Rank 3 | AQI ~170)
Kolkata’s air quality is influenced by industrial emissions, traffic congestion, coal usage, and high humidity that limits pollutant dispersion. Ageing vehicles and dense urban layouts exacerbate exposure, pushing AQI levels into unhealthy territory.
Dhaka, Bangladesh (Rank 4 | AQI ~162)
Dhaka remains one of the world’s most consistently polluted cities. Brick kilns, construction activity, unregulated industries, and extreme population density drive chronic PM2.5 exposure. Even on non-peak days, air quality rarely meets safe standards.
Lahore, Pakistan (Rank 5 | AQI ~160)
Lahore experiences severe smog episodes driven by vehicular emissions, industrial output, and agricultural residue burning. Weak enforcement of emission norms allows pollution levels to rise sharply during winter months.
Manama, Bahrain (Rank 6 | AQI ~158)
Despite high income levels, Manama struggles with air pollution due to oil refining, traffic emissions, and desert dust. Limited green cover and fossil-fuel dependency highlight that economic prosperity does not automatically translate into clean air.
Kampala, Uganda (Rank 7 | AQI ~158)
Kampala’s inclusion reflects rapid urbanisation without adequate environmental safeguards. Open waste burning, traffic growth, and industrial expansion have significantly degraded air quality in recent years.
Doha, Qatar (Rank 8 | AQI ~157)
Doha’s pollution is linked to high per-capita energy consumption, desalination plants, vehicular traffic, and natural dust storms. The city illustrates how energy-intensive lifestyles can drive poor air quality even in planned urban environments.
Karachi, Pakistan (Rank 9 | AQI ~157)
Industrial zones, port operations, oil-based power plants, and poorly maintained vehicles contribute to Karachi’s persistent pollution problem. Coastal winds offer limited relief amid rising emission loads.
Mumbai, India (Rank 10 | AQI ~152)
Mumbai’s pollution comes from construction dust, traffic congestion, landfill fires, and industrial emissions. Although coastal winds help disperse pollutants, rapid urban development continues to offset these natural advantages.
1. South Asia as the Global Pollution Epicentre
Four of the ten cities are from India, Pakistan, and Bangladesh. This reflects shared challenges such as population density, fossil-fuel reliance, construction-driven growth, and regional agricultural practices.
2. Pollution Is Not Just a Developing-Nation Problem
Cities like Doha and Manama demonstrate that wealth alone cannot guarantee clean air. Policy choices, energy models, and regulatory enforcement matter more than income levels.
3. Daily AQI Spikes Signal Structural Failure
Daily rankings reaching “Very Unhealthy” levels indicate that pollution controls are insufficient to prevent acute exposure events, even if annual averages appear slightly lower.
When AQI exceeds 150:
Respiratory distress increases across all age groups
Heart attack and stroke risks rise significantly
Children and the elderly face immediate danger
Outdoor activity becomes unsafe
Repeated exposure to such daily spikes accelerates long-term health damage, reducing life expectancy and increasing chronic disease prevalence.
High AQI days reduce urban productivity, strain healthcare systems, and degrade ecosystems. Visibility loss, acid deposition, and heat absorption by particulate matter further destabilise urban environments. Over time, polluted cities become less livable, less attractive to investment, and more expensive to govern.
Annual averages often mask the severity of short-term exposure. Daily AQI snapshots reveal:
How often cities cross emergency thresholds
Which populations face immediate health risks
Whether policy measures are effective in real conditions
For policymakers, researchers, and citizens, these rankings are a real-time accountability tool.
This daily AQI ranking underscores a sobering reality: the world’s most polluted cities are concentrated in regions where urban growth has outpaced environmental protection. Delhi’s position at the top is not an anomaly-it is a warning signal. Without sustained policy reform, clean energy transitions, and regional cooperation, such rankings will continue to repeat themselves.
Air pollution is no longer an invisible threat. It is measurable, predictable, and preventable. What remains uncertain is whether governments will act with the urgency that public health demands.