Guardian: The air quality legacy of the Beijing Olympics looks set to linger a little longer after the Chinese capital announced a 12-month extension of traffic restrictions imposed ahead of last year’s games plus more stringent measures targeting high-emissions vehicles. A fifth of the city’s 3.6m private vehicles and a third of official cars will continue to be barred from the roads every weekday, the Beijing Traffic Management Bureau has said. By keeping these vehicles off the road, …