Obama reverses Bush pollution policy

US President Barack Obama today opened the way for American states to impose stricter pollution laws in a major reversal of the Bush administration's environment policy.

The president ordered the Environmental Protection Agency (EPA) to review its decision to reject a request from California to set its own exhaust emissions standard, a move that would force carmakers to cut the greenhouse gas emission of new vehicles.

At least 13 other states have also applied for a waiver, needed under the US's Clean Air Act, which would allow them to introduce their own car pollution limits.