Brownfields are previously developed properties that may be contaminated or have environmental concerns, making them less attractive for redevelopment. These sites can include abandoned factories, old gas stations, or industrial areas. The presence of pollutants can hinder new construction or use, but many brownfields are safe for redevelopment with proper cleanup. Efforts to rehabilitate brownfields can lead to revitalization of communities, creating new jobs and housing. Government programs often provide funding and support for cleanup initiatives, encouraging investment in these areas. Redeveloping brownfields can also help reduce urban sprawl and promote sustainable land use practices.