WASHINGTON — Under the banner of clean energy, Earth Day participants celebrated Saturday in the nation's capital and at thousands of events around the globe in an extravaganza of entertainment, advocacy and politics.

Environmentalists and supporters participated in events in 183 countries for the 30th Earth Day.

Thousands of people gathered peacefully at the Mall in Washington, less than a week after hundreds of demonstrators were arrested here, protesting the global activities of international lending agencies. Among other things, those protesters had objected to the environmental policies of the World Bank and International Monetary Fund.

Saturday's rallies were organized by the Seattle-based Earth Day Network, whose chairman, Denis Hayes, was the national coordinator for the 1970 event. The teach-ins and rallies of that original Earth Day, more informal and less global, helped inaugurate the modern environmental movement in the United States and was the spark for two landmark environmental laws signed by President Richard M. Nixon, the Clean Air Act and the Clean Water Act.

In his radio address Saturday, President Clinton announced two new but relatively modest initiatives to combat global warming and celebrate Earth Day. Clinton said he was going to require federal agencies to reduce by 20 percent over five years the amount of gasoline their vehicle fleets consume. This would save 45 million gallons of oil a year.

Clinton also announced a program to allow federal workers to set aside up to $65 tax-free every month to pay for public transportation.

Saturday's celebration in Washington, called EarthFair 2000, was not politically diverse. But the rally's loosely organized format made for some interesting contrasts.

Actor Leonardo DiCaprio led the festivities. DiCaprio, 25, was scheduled to be a host on an Earth Day special on the ABC television network Saturday night. Saturday's rallies also featured speakers who back a campaign seeking to raise the environmental conscience of some prominent corporations, like Walt Disney Co., which owns ABC and will distribute a movie starring DiCaprio.