Thirty years after the first Earth Day galvanized public support for environmental protection laws, Americans enjoy purer air and cleaner water. Fish have returned to polluted rivers, toxic wastes have been reduced and endangered species rescued from imminent extinction. But many experts say further progress will be harder to achieve on remaining environmental challenges, such as global warming, water pollution from multiple sources and urban sprawl. Some in the business community say the tradi-tional, regulatory approach to environmental protection must give way to state and local initiatives and voluntary efforts by businesses, consumers and other potential polluters.
New condominiums edge toward the mountains in the south Denver suburb of Littleton. Environmentalists say urban sprawl in cities like Denver is one of the nation's major environmental problems.