Fog: meaning, definitions and examples

Thick cloud near the ground that makes it hard to see. It usually forms when there's a large amount of water vapor in the air and cooling temperatures.

• The fog was so dense that I couldn't see the road signs.
• We had to delay our flight because of the heavy fog.

Light cloud near the ground, usually caused by humidity or hot and cold air meeting. It’s generally less thick than fog.

• In the morning, the garden was covered with mist.
• The mist began to clear as the sun rose.

Light mist or smoke in the air that makes it hard to see far away. It’s often caused by pollution or heat.

• The city was covered in a light haze from the car exhaust.
• There was a haze over the mountains due to the forest fires.

Dirty fog mixed with smoke and pollutants, typically found in cities. It is harmful to health and the environment.

• The smog in Beijing was so severe that people wore masks outside.
• The city's smog problem has worsened due to increased industrial activity.
• Smog is a significant health risk for people living in urban areas.