Question

How does it harm the environment?

Answer 1

Your question is unclear. It either must be What harms the environment or how can humans harm the environment.

Anyways,

What actually harms the environment?

Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation. Changes like these have triggered climate change, soil erosion, poor air quality, and undrinkable water.