CLEARING THE AIR: One of Beijing's worst rounds of air pollution kept schoolchildren indoors and sent coughing residents to hospitals Monday, but this time something was different about the murky haze: the government's transparency in talking about it.

NEW PRESSURE: Beijing's new openness about smog also put more pressure on the government to address underlying causes, including a lag in efforts to expand emissions limits to all of the vehicles in Beijing's notoriously thick traffic.

WHAT THEY DID: Government officials — who have played down past periods of heavy smog — held news conferences and posted messages on microblogs discussing the pollution.