Beijing issues smog red alert, urging schools to close
Beijing has issued its first red alert for smog.
Authorities are urging schools to close and invoking restrictions on factories and traffic that will keep half the city's vehicles off the roads.
The red alert - the most serious warning on a four-tier system adopted in recent years - was announced late on Monday. It means authorities have forecast more than three consecutive days of severe smog.
Readings of PM2.5 particles climbed toward 300 micrograms per cubic meter, compared with the World Health Organisation's safe level of 25. The heavy smog is not expected to improve until Thursday.
It is the second time this month that notoriously polluted Beijing has experienced a prolonged bout of smog.
Most of the pollution is blamed on coal-fired power plants, along with vehicle emissions and construction and factory work.
An online notice from the Beijing Municipal Environmental Protection Bureau said it issued the alert to "protect public health and reduce levels of heavy air pollution".
Along with school closures and limiting cars to driving every other day depending on the last number of their licence plate, a raft of other restrictions will seek to reduce the amount of dust and other particulate matter in the city of 22.5 million people. Officials said extra subway trains and buses would be added to handle the additional strain on public transport.
Beijing was also shrouded in persistent smog for most of November, when power demand soared due to unusually cold weather.
While pollution in the capital improved slightly in the first 10 months of the year, heavy smog that can be seen from space regularly forces Beijing schools to suspend outdoor activities and can even prompt highway closures because of reduced visibility.
There have previously been stretches of severe smog that lasted more than three straight days. However, those had been forecast to last three days or less, so they did not trigger a red alert. The alert requires a forecast of more than 72 straight hours with PM2.5 levels of 200 micrograms per cubic meter or more.
Polluted air throughout broad swaths of China has had severe health effects. A study led by atmospheric chemist Jos Lelieveld of Germany's Max Planck Institute and published this year in Nature magazine estimated that 1.4 million people die prematurely because of pollution in China each year.
China, the world's biggest carbon emitter, plans to upgrade coal power plants over the next five years to tackle the problem, and says its emissions will peak by around 2030 before starting to decline.
While emissions standards have been tightened and heavy investments made in solar, wind and other renewable energy, China still depends on coal for more than 60% of its power.