A coalition of health and environmental groups is suing the Environmental Protection Agency, challenging its determination last week that revoked a scientific finding that has been the central basis for U.S. action to regulate greenhouse gas emissions. A rule finalized by the EPA on Thursday rescinds a 2009 government declaration known as the endangerment finding that determined that carbon dioxide and other greenhouse gases threaten public health and welfare. The Obama-era finding is the legal underpinning of nearly all climate regulations under the Clean Air Act for motor vehicles, power plants and other pollution sources that are heating the planet. The lawsuit calls the EPA's action unlawful and says the 2009 finding supported common sense safeguards to cut climate pollution.