But muggy air smothered Beijing over the weekend, sending its air pollution index above 100, the maximum level for what officials call the citys blue sky days, or days of acceptable air quality.

• 但就在措施启动后的第一个周末，北京又笼罩在闷热的空气中，空气污染指数超过了100，这个数字是官方认为能够看见蓝天（也就是空气质量勉强达标）的最高污染水平。