Beijing has vowed the Olympic Games will take place under blue skies, not the murky "sauna" haze that has shrouded the city recently, but even on apparently clear days pollution levels may not be safe for athletes. Officials lavished 120 billion yuan ($17.6 billion) on cleaning up the capital with factories dozens of miles away closed down, construction halted, and over half the city's 3.3 million cars cleared from the roads.