What is Earth Day?
Answer
A day celebrating and protecting the environment
Explanation
Earth Day is an annual observance celebrating and protecting the environment, held in the United States and now around the world on April 22. The first Earth Day was organized on April 22, 1970 by Senator Gaylord Nelson of Wisconsin, a Democrat who had spent the late 1960s pushing for greater national attention to pollution, and by Denis Hayes, a 25-year-old Stanford graduate student whom Nelson hired as the national coordinator. About 20 million Americans (roughly 10 percent of the population at the time) participated in rallies, teach-ins, and demonstrations on that first Earth Day, making it one of the largest single-day public events in U.S. history. The teach-in format, modeled on the antiwar teach-ins of the late 1960s, emphasized education and grassroots organizing in schools, college campuses, churches, and community centers.
The political effect was substantial. By the end of 1970, the same Congress that had been largely silent on environmental matters had created the U.S. Environmental Protection Agency (established by Reorganization Plan No. 3 of 1970, effective December 2, 1970, signed by President Richard Nixon) and passed the Clean Air Act Amendments of 1970 (Public Law 91-604, December 31, 1970). Over the next several years Congress passed the Clean Water Act of 1972 (Federal Water Pollution Control Act Amendments), the Endangered Species Act of 1973 (Public Law 93-205), and the Safe Drinking Water Act of 1974 (Public Law 93-523).
Earth Day became an annual observance in the United States and spread internationally; in 1990, Denis Hayes coordinated a 20th anniversary global Earth Day with about 200 million participants in 141 countries. The Paris Agreement on climate change was opened for signature on Earth Day, April 22, 2016.
Earth Day is not a federal public holiday under 5 U.S.C. section 6103, but it is widely observed in schools, universities, government agencies, businesses, and community organizations through environmental education, tree planting, neighborhood cleanups, recycling drives, climate marches, and other activities. The U.S. Environmental Protection Agency, the National Park Service, the Forest Service, and many state agencies use Earth Day to launch environmental initiatives. The day shares thematic territory with Arbor Day (last Friday in April) and is sometimes celebrated jointly with it. Earth Day is now coordinated internationally by EarthDay.org (formerly the Earth Day Network), a 501(c)(3) nonprofit founded by the original organizers.
Why this matters for your test
Understanding what Earth Day is connects applicants to a major American civic observance that catalyzed federal environmental law and continues to organize public attention to pollution and climate change. It also illustrates how a single grassroots event can produce lasting institutional change at the federal level.
Source: USCIS 128 Civics Questions (2025)
