Exercising the right to a sustainable and healthy environment requires the ability to participate in government and business decisions that affect the environment. A global coalition of public interest groups and research organizations measured the public's ability to participate in such decisions in nine countries representing a range of income levels and development paths. The investigation assessed the three elements of public participation as defined at the Rio Earth Summit in 1992: access to information, access to the decision-making process, and access to redress. The results show that, despite considerable progress in these areas, serious gaps remain in the public's ability to participate in important environmental decisions. These gaps occur in both developed and developing nations, and reflect limited articulation of participation rights in national law and institutional practice. The results also suggest that the public is often unfamiliar with and unaccustomed to exercising the rights they already have.