1. the presence of harmful or poisonous substances in the environment
2. the action of making something dirty or impure

Examples

• Air pollution from factories affects the health of nearby residents.
• The oil spill caused severe water pollution in the bay.
• Noise pollution from traffic makes it hard to sleep at night.
• The government passed new laws to reduce industrial pollution.
• Plastic pollution threatens marine life in our oceans.
• Light pollution makes it difficult to see stars in the city.
• Chemical pollution has contaminated the groundwater supply.