If the air is smoggy, it is dirty and hard to see through because of pollution.
Smoggy air is bad and unhealthy. It can make people sick and is not good for the earth.
Examples:
The city is smoggy today.
I don't like to go outside when it's smoggy.
The smoggy air makes it hard to breathe.
The smoggy air is like a big dirty blanket over the city.
In some places, the air is so smoggy you can't see the sun.
The smoggy air smells bad and makes my eyes hurt.