Half of Beijing's private cars were ordered off the streets on Tuesday and many construction sites and schools were closed under the Chinese capital's first-ever red alert for pollution.
A grey haze descended on the city of around 21.5 million people, with levels of PM2.5 - harmful microscopic particles that penetrate deep into the lungs - at one point above 300 micrograms per cubic metre according to the U.S. embassy, which issues independent readings. The World Health Organisation's recommended maximum exposure is 25. The alert coincided with global climate change talks in Paris, where Chinese President Xi Jinping has vowed "action" on greenhouse gas emissions.
Most of China's greenhouse gas emissions come from the burning of coal for electricity and heating, which spikes when demand peaks in winter and is the main cause of smog. It was the first time authorities declared a "red alert" since emergency air pollution plans were introduced two years ago, although levels were far from the city's worst. It came a week after thick grey smog shrouded Beijing, cutting visibility severely and sending PM 2.5 levels as high as 634 micrograms per cubic metre.
Under the alert - the highest in a four-tiered, colour-coded warning system - an odd-even number plate system bans half the city's roughly 4.4 million private cars from the streets on alternate days. Outdoor construction sites are ordered to close and some industrial plants told to cease or reduce operations.
Authorities in the capital were heavily criticised after only issuing an orange alert for last week's pollution.AFP
