Smog returns, but Beijing says skies are getting cleaner

The Chinese capital was on the second-highest orange smog alert in the depth of winter on Tuesday but city officials said the air quality was improving overall, citing data for last year. Hundreds of flights were cancelled and highways closed across northern China over the new year holiday as average concentrations of small breathable particles known as PM2.5 soared above 500 micrograms per cubic metre in Beijing and surrounding regions. Pollution alerts are common in northern China, especially