Well, it’s finally happened: a year and a half after denying California’s petition to set its own greenhouse-gas emissions standards for vehicles, the US Environmental Protection Agency has reversed itself and granted the waiver request. That’s what a change of administration will get you in Washington.

Lisa Jackson, the EPA’s new administrator under President Barack Obama, said she had “decided this is the appropriate course under the law”. The prior administrator, Stephen Johnson, rejected California’s request and said that a national standard was needed, not a patchwork of state regulations. In April, the EPA declared carbon dioxide emissions a danger to human health.

California requested the waiver in 2005; it regularly asks for national standards to be waived so that it can set more stringent environmental standards.

Interest groups were split along predictable lines in their reaction. Reuters points out that the American Petroleum Institute argues that the waiver will “impose costly requirements” on businesses. David Doniger of the Natural Resources Defense Council called the waiver granting “a win for everyone”.