Beijing is seeking to tame the spikes in its infamous smog by preparing emergency measures such as factory shutdowns and traffic limits to kick in when air pollution levels are especially heavy.
The city government said Tuesday the strictest emergency measures will take effect when the pollution index for fine particulate matter, PM2.5, is forecast to exceed 300 micrograms per cubic meter for three days running.
Private vehicles will be allowed to operate only on alternating days, depending on the last number of their license plates. Factory emissions will be cut 30 percent by suspending or limiting production, and construction sites must halt excavation and demolition work. Classes will be suspended, a measure likely to cause inconvenience in a city where most parents both work.
The measures require precise pollution forecasting and timely public notification to be effective, and there was obvious skepticism in the questions asked by Chinese reporters at a briefing announcing the emergency measures.