Live data from 30,000+ monitoring stations in 180 countries
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Enter any two cities worldwide and press Compare
AQI Scale Position
0 Good50100150200300+
🌎 Why Compare City Air Quality?
Air quality varies enormously between cities, sometimes by a factor of 50x or more. A winter day in Delhi can expose you to the equivalent of 10 to 15 cigarettes per day of particulate intake, while a day in Reykjavik registers less than 0.1. Comparing cities helps you make smarter decisions about travel, relocation, and outdoor activity.
This tool pulls live data from the World Air Quality Index (WAQI) network, the largest air quality data platform in the world, using geocoding to find the nearest verified monitoring station to each city you enter.
⚙️ How the Tool Works
Type any two city names with country for precision, for example London, UK rather than just London. The tool first converts the city name to coordinates using the Open-Meteo geocoding API, then queries the nearest WAQI monitoring station for live AQI, PM2.5, PM10, and cigarette equivalent exposure.
The cigarette equivalent is based on the Berkeley Earth methodology: 22 micrograms per cubic metre of PM2.5 per 24 hours equals approximately one cigarette of particulate intake.
❓ Frequently Asked Questions
Which city has the worst air quality in the world right now?
South Asian cities consistently rank at the top. Delhi, Lahore, Dhaka, and Kathmandu frequently record AQI above 300 during winter months. Use this tool to compare any two cities and see today’s real reading.
What is a safe AQI level?
The US EPA considers AQI 0 to 50 as Good and safe for everyone. AQI 51 to 100 is Moderate. Above 100, sensitive groups should limit outdoor time. Above 150, everyone is affected. Above 200, everyone should avoid outdoor activity.
Can I compare cities in different countries?
Yes. AQI is standardised globally using the US EPA scale, making comparisons between any two cities directly meaningful regardless of which monitoring agencies operate in each country.
How fresh is the air quality data?
WAQI stations update hourly. Dense urban stations in major cities often update every 15 to 30 minutes. The station name shown under each city indicates exactly which monitoring point is used.
What does the cigarette equivalent figure mean?
Berkeley Earth researchers calculated that breathing 24 hours of air at PM2.5 of 22 micrograms per cubic metre delivers a similar particulate dose to smoking one cigarette. This gives a relatable health communication benchmark beyond abstract AQI numbers.