Montreal ranks as one of the ‘world’s most polluted’ major cities

Montreal's air quality dropped to make the city one of the worst on the planet on July 15, 2025, thanks to wildfires in Ontario.

Montreal has been named one of the “most polluted major cities” in the world on Tuesday morning.

The air quality currently sits at an “unhealthy” level of 152, according to IQAir, a Swiss company that specializes in protecting against airborne pollutants, developing air quality monitoring and air cleaning products.

Updates to the index are provided on an hourly basis, comparing 126 major cities across the globe.

As of 8:30 a.m., Montreal is in sixth position.

The only cities that tested worse are:

• Kinshasa, COD
• Santiago, CHL
• Baghdad, IRQ
• Hanoi, VNM
• Manama, BHR

The only other Canadian city to make the top 10 is Toronto, Ont., with a level of 111.

Contrarily, Vancouver, BC. ranked the world’s best city when it comes to air quality with a rating of 13.

IQAir recommends that Montrealers wear a mask when outside, avoid outdoor exercise, close windows to avoid dirty air and run an air purifier if possible.

Overall, the company notes that Montreal usually does have good air quality, “despite a large and ever-growing population coupled with extensive industry and other related anthropogenic activity.”