Summary
Smoggy skies turned clear in parts of China Thursday after nearly a full week of severe pollution which saw scores of flights cancelled and forced the closure of schools in some areas.
Levels of the smaller PM 2.5 particles, tiny enough to be absorbed into the bloodstream and thought to be a major contributor to respiratory and cardiovascular disease, reached more than 29 times the World Health Organization's daily recommended maximum.
Within hours, PM 2.5 levels in Beijing dropped by some 90 percent.
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