To encourage pollution prevention, communities that host manufacturing facilities must understand the products and processes used by industry and the by-products and pollution that they create locally.
A community's pressure on polluters is affected by its income, education, the size of the exposed population, the local economic importance of the plant, and the plant's visibility as a polluter.
Evidence from Asia, Latin America and North America suggests that neighboring communities can have a powerful influence on factories' environmental performance. Communities which are richer, better educated, and more organized find many ways of enforcing environmental norms. Where formal regulators are present, communities use the political process to influence the tightness of enforcement. Where formal regulators are absent or ineffective, 'informal regulation' is implemented through community groups or NGOs.
The agents of informal regulation vary from country to country -- local religious institutions, social organizations, community leaders, citizens' movements or politicians. Factories negotiate directly with local communities, responding to social norms and/or explicit or implicit threats of social, political or physical sanctions if they fail to reduce the damages caused by their emissions. In countries as different as China, Brazil, Indonesia and the US, much of the variation in factories' environmental performance is explained by inter-community variation in income, education and bargaining power.