Guardian: The mayor of London’s proposed changes to the Congestion Change scheme could exacerbate the capital’s air pollution problems and stifle take-up of electric cars, campaigners said today. The changes will also mean that tens of thousands of hybrid owners will lose their exemption status. The warning comes as a major carmaker launches a campaign to create a consumer label showing cars’ air pollution impact. In May, Boris Johnson proposed a “greener vehicle discount” …