Beijing air pollution
The Chinese capital has for many years suffered from serious air pollution. Primary sources of pollutants include exhaust emission from Beijing's more than five million motor vehicles, coal burning in neighbouring regions, dust storms from the north and local construction dust. A particularly severe smog engulfed the city for weeks in early 2013, elevating public awareness to unprecedented levels and prompting the government to roll out emergency measures.
Public anger in Beijing as authorities fail to post the highest smog alert
Public anger continued to rise in Beijing yesterday at the city government's failure to issue a top-level smog alert after days of heavy pollution, though the air started to clear in the evening as a cold front brought rain and wind.
The Beijing Environmental Bureau removed an orange alert for smog - the second in a four-tier system - that had been in place since Friday, as the official Air Quality Index dropped from above 500 to about 460 at 5pm.
At the US embassy, the PM2.5 reading - which measures tiny pollutant particles that are the deadliest - dropped from 551 micrograms per cubic metre at noon to 446 in the afternoon, still a hazardous level.
The city's meteorological centre has issued 12 smog alerts since February 20. Nine were yellow alerts, the third-highest on the scale, which means people must stay indoors; three were orange, which require a halt to construction, barbecues and fireworks. But Beijing has been under public pressure to issue the highest alert - red - which calls for measures such as closing schools to minimise the impact on health.
A school affiliated to Peking University suspended some classes on Tuesday and Wednesday, though the education committee ordered them to resume yesterday, China National Radio and the Beijing News said.
"Nanjing suspended schools for four days late last year," one microblogger wrote. "This heavy smog has been going on for seven days in Beijing, and they still want our kids to go to school. This is beyond understanding."
A Beijing environmental bureau spokesman said the pollution was not bad enough to activate the red alert.
Greenpeace campaigner Huang Wei said the emergency responses had failed to meet high public expectations. "The officials are not proactive enough. They should listen to public opinion when setting the conditions [for the alerts]."
On Tuesday President Xi Jinping told Beijing city officials to strengthen efforts to curb air pollution, state media reported yesterday. Xi said the priority was to limit PM2.5 levels. This could be achieved by reducing dependence on coal, strictly controlling vehicles and readjusting the industrial structure.
Watch: Beijing targets steel mills to cut air pollution
Up to 15 per cent of the country has been blanketed by hazardous pollution over the past week, with more than 19 cities recording PM2.5 levels far exceeding the World Health Organisation's safe level.