President Trump is set to significantly weaken a set of environmental rules to make it easier for developers and corporations to build mines, expand airports, and lay gas and oil pipelines, The Washington Post reports. The proposed changes, which the newspaper says will be unveiled Tuesday, would slacken the National Environmental Policy Act. The act requires federal agencies to assess the impact of big infrastructure projects on natural resources before they break ground, and it has previously been invoked by environmental activists to challenge controversial projects. President Trump said on the act’s 50th anniversary last week that it “can increase costs, derail important projects, and threaten jobs for American workers and labor union members.” Trump now wants to redefine what constitutes a “major federal action” in order to exempt projects without significant federal funding from the environmental reviews. However, the proposal will almost certainly face legal challenges.