An E.U.-mandated shift to diesel cars has sent London’s NO2 emissions through the roof. “It’s a public-health catastrophe,” says one prominent campaignerBritish tabloids may lash out at Chinese smog all they want, but when it comes to one important pollution indicator, the U.K. capital actually outpollutes even Beijing.A European Union–wide shift to diesel, in order to curb CO2 emissions, has sent London’s nitrogen dioxide levels through the roof, Bloomberg reports. Not only are they the worst in Europe, reaching twice the E.U. limit, they also surpass the Chinese capital’s by a whopping 50%.

“Successive governments knew more than 10 years ago that diesel was producing all these harmful pollutants, but they myopically plowed on with their CO2 agenda,” Simon Birkett, founder of the nonprofit Clean Air in London, told Bloomberg. “It’s a public-health catastrophe.”

In 2000, the E.U. drew up rules allowing diesel cars to discharge more than three times the amount of nitrogen dioxide than those using gasoline.

“We’re stuck now with these diesel cars,” says Matthew Pencharz, the environment and energy adviser to the mayor of London. “About half our cars are diesel, whereas 10 or 15 years ago it was lower than 10%.”

Nitrogen dioxide irritates the lungs, increasing susceptibility to respiratory infections. In China, efforts are mostly focused on other pollutants, such as PM10, levels of which almost triple those in London.

via London Is a Worse Nitrogen Dioxide Polluter Than Beijing | TIME.