Brownfield status means that a piece of land used to have something on it that could be harmful to people or the environment. It's like if you spilled juice on the carpet and didn't clean it up right away - it could leave a stain and make the carpet sticky or smelly.
The things that could be harmful on brownfield land are usually things like chemicals or pollutants from factories, gas stations, or other businesses that used to be there. If these things aren't cleaned up, they could make people sick or hurt the environment.
When a piece of land is given brownfield status, it means that the government or another group has recognized that there might be something harmful on the land and they want to make sure it gets cleaned up properly. Sometimes this means that the land can't be developed until it's properly cleaned, while other times development can happen while cleanup is ongoing.
Ultimately, the goal of giving land brownfield status is to make sure that people and the environment are kept safe and healthy, and that the land can be used in a way that won't cause harm in the future.