(KDVR) — Wildfires in Canada have caused poor air quality and smoky skies across several U.S. metros for days. On Wednesday, the air quality in New York City was ranked the worst in the world.

That’s according to IQAir’s Air Quality and Pollution City Ranking, which is updated hourly, the air pollution advocacy organization explains. It’s important to note that while New York City is currently in the top spot for unhealthy air, it will likely drop back down once the aforementioned smoke disappears. A few weeks ago, Denver, Colorado, was ranked among the top 10 worst in the world due to wildfire smoke. As of Wednesday, the city ranked 96th on IQAir’s list.

IQAir’s live Air Quality and Pollution City Ranking ranks cities based on AQI, or Air Quality Index points. Cities/areas are assigned a series of ranges for how healthy or unhealthy the air currently is.

How to check the air quality where you live

To find your city/area, you’ll need to allow IQAir to access your location. Once the system locates you, it’ll give you your area’s AQI, in addition to which main pollutant is contributing to the pollution level.

Ranges include: Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous. New York City’s air on Wednesday is the only city on the entire list given a Hazardous air rating.

As of Thursday afternoon, the real-time rankings for the most polluted Indiana city are fluctuating between Ferdinand and Tell City. Ferdinand had an average air quality index of 157, while Tell City had an average air quality index of 155, both of which indicate the air is ultimately not safe for sensitive groups.

According to the EPA, sensitive groups include people with heart and lung disease, older adults, children, people with diabetes, and those of a lower socioeconomic status.

To be clear, IQAir’s real-time city rankings change as the average air quality index improves or worsens for any given city.”

Meanwhile, Chesterton currently has the cleanest air in Indiana, according to IQAir’s rankings Thursday afternoon. The city boasts an air quality index of 40, which is a “good” level of pollution, according to the website.

Aside from New York City, the next highest U.S. city on the air quality ranking is Detroit, Michigan (23), which claimed “moderate” air quality levels Wednesday evening. India dominated the top 5, with the cities of Delhi and Kolkata ranking third and fourth, respectively, and claiming Unhealthy air ratings.

The second highest city on the list is Dubai, UAE, whose air was ranked unhealthy.

Is the smoke dangerous?

Will the level of smoke be dangerous for your health? Here’s what the Colorado Department of Public Health and Environment said people everywhere should know.

“If smoke is thick or becomes thick in your neighborhood, you may want to remain indoors. This is especially true for those with heart disease, respiratory illnesses, the very young, and the elderly. Consider limiting outdoor activity when moderate to heavy smoke is present. Consider relocating temporarily if smoke is present indoors and is making you ill,” CDPHE said.

If visibility is less than 5 miles in your neighborhood, the smoke has reached levels that are unhealthy, and you should stay indoors.

You can visit the Centers for Disease Control and Prevention for more information on wildfire smoke hazards.