The introduction of chemical, physical, or biological agents into water that degrade it is called water pollution.

Here's a breakdown:

* Chemical pollution: Includes substances like pesticides, fertilizers, industrial chemicals, and pharmaceuticals.

* Physical pollution: Refers to things like heat, sediment, and plastic debris.

* Biological pollution: Involves the introduction of harmful microorganisms like bacteria, viruses, and parasites.

All of these factors can significantly impact water quality and make it unsafe for human consumption, aquatic life, and recreation.