There was a time when skyscrapers in Beijing were often barely visible. Today, people can see them rise into crisp blue sky almost every day. Outcome of a decade of clean air policy. 曾經有一段時間，北京的摩天大樓幾乎難以察覺。如今，人們幾乎每天都能看到它們聳立在湛藍的天空中。這是十年清潔空氣政策的成果.