The 1970s proved to be a pivotal period for the anti-nuclear movement in California. There was confrontation between nuclear power advocates and environmentalists. In 1981, 1,900 activists were arrested during protests at Diablo Canyon Power Plant. In 1984, the Davis City Council declared the city to be a nuclear free zone. California has banned the approval of new nuclear reactors since the late 1970s because of concerns over waste disposal.