why is there chlorine in a swimming pool?

Question: why is there chlorine in a swimming pool?
- Keywords:
  chlorine,
  element,
  swimming pool
Asked by daisy147 to William, Roberto, Karen, Jasmine, Chinna on 14 Nov 2018.
- Chinna answered on 14 Nov 2018:
  
  Chlorine can kill the bacteria in the water. So to sterilise the water in swimming pools, they mix it with chlorine.

Question: why is there chlorine in a swimming pool?