smog

/smɑɡ/
noun
  1. A thick, hazy form of air pollution caused by a mixture of smoke, fog, and chemical fumes, often found in cities.
    • The city was covered in thick smog, making it hard to see the buildings across the street.
    • Many people wear masks outdoors to protect themselves from the smog.
    • Factories and cars are the main sources of the smog that hangs over the valley.
Synonyms