A more thorough explanation:

An environmental-impact statement is a document that a federal agency must create for a major project or legislative proposal. The purpose of this document is to evaluate the positive and negative effects that the project or proposal may have on the environment. This helps decision-makers make informed choices about whether or not to move forward with the project or proposal.

For example, if a company wants to build a new factory in a rural area, they would need to create an environmental-impact statement. This document would evaluate the potential effects of the factory on the local environment, such as air and water quality, wildlife habitats, and noise pollution. The statement would also suggest ways to mitigate any negative effects.

Another example would be if a city wanted to build a new highway. An environmental-impact statement would evaluate the potential effects of the highway on the surrounding environment, such as air and water quality, wildlife habitats, and noise pollution. The statement would also suggest ways to mitigate any negative effects, such as building sound barriers or planting trees to absorb pollution.