BEIJING (Reuters) - China's efforts to clear the skies over its polluted capital are having an effect, officials said on Friday, insisting that Beijing's air would be safe for Olympic athletes despite persistent smog over the city. Beijing authorities have taken cars off the road and opened new subway lines in the past week, in addition to halting some construction and suspending factory production, in a last-ditch effort to ensure clear skies when the Games open on August 8. "For the effects of the measures we have taken to be increasingly felt, we will have to make continued efforts," Du...