Beijing remained cloaked in heavy smog hiding much of its skyline Tuesday as parts of northern China suffered a sixth straight day of severe pollution, despite the announced closures or production cuts at 147 of the city's industrial plants.

On Tuesday morning, readings of particulate matter known as PM2.5, a key measure of pollution, reached 444 micrograms per cubic meter in central Beijing, according to the National Meteorological Center. The World Health Organization considers 25 micrograms a safe level. 

"Of course, on days where pollution levels reach or even exceed the scale we are very concerned and we have to see this as a crisis," Bernhard Schwartlander, the WHO's representative in China, told Reuters.

"There's now clear evidence that, in the long term, high levels of air pollution can actually also cause ... lung cancer."

The meteorological centre said moderate or severe pollution had persisted in northern China since Thursday, and that it was particularly serious in Beijing and its surrounding area. It forecast that the pollution would continue in parts of eastern, northern and central China until Wednesday evening, when precipitation and wind should help to disperse it.

The smog is so bad even the statues wear masks — or at least they do in pictures of a campus stunt that circulated online Tuesday.

After being stuck inside because of the bad air, a psychology student at Peking University ventured out to place the masks on campus statues of Spanish novelist Miguel de Cervantes, Communist Party co-founder Li Dazhao and a sage practising tai chi.

"I was feeling really low, so I came up with this idea," Jiang Chao said in a telephone interview.

A rare visit

Chinese President Xi Jinping braved Beijing's choking smog Tuesday, making an unannounced visit to a trendy alley and sitting with residents in his latest public relations effort to be seen as a man of the people.

Guan Shiyue, a 69-year-old retiree who lives in a small, sparsely furnished home on a nearby alley, said Xi visited him and sat between him and his wife on their living room sofa. Guan said he was impressed by the president.

China Pollution

Pedestrians cross an overhead bridge as vehicles clog a main highway during a sixth straight day of severe pollution in Beijing on Tuesday. Hazardous white pollution continues to hide much of Beijing's skyline despite announced closures or production cuts at 147 of the city's industrial plants. (Ng Han Guan/Associated Press)

"He's a good leader of the ordinary people ... I think he does things in a particularly practical way," Guan told The Associated Press. "The leaders of this new generation are capable."

Such visits are extremely rare for top Chinese leaders, who are not known for mingling with the public other than at scheduled events. Given Xi's status and China's conservative political culture, his appearance was likely stage-managed to some degree beforehand.

Though Xi was unaccompanied by most state media, their reports conveyed his campaign's likely message. "Xi Jinping visits Beijing's Nanluoguxiang amid the smog: Breathing together, sharing the fate," read the headline of a Xinhua News Agency report.

Resident sues government over smog

Meanwhile, a Chinese man in a smoggy northern city has become the first person in the country to sue the government for failing to curb air pollution, a state-run newspaper reported on Tuesday.

Li Guixin, a resident of Shijiazhuang, capital of Hebei province, has submitted his complaint to a district court, asking the Shijiazhuang Municipal Environmental Protection Bureau to "perform its duty to control air pollution according to the law", the Yanzhao Metropolis Daily said.

He is also seeking compensation from the agency for residents for the choking pollution that has engulfed Shijiazhuang, and much of northern China, this winter.

"The reason that I'm proposing administrative compensation is to let every citizen see that amid this haze, we're the real victims," Li was quoted as saying by the newspaper.

It is unclear whether the court will accept Li's lawsuit.

His lawyer, Wu Yufen, declined to comment, telling Reuters "this information is quite sensitive." The court and the Shijiazhuang environmental protection bureau could not be reached for comment.

Li said he had spent money on face masks, an air purifier and a treadmill to get indoor exercise last December when the pollution was particularly severe.

"Besides the threat to our health, we've also suffered economic losses, and these losses should be borne by the government and the environmental departments because the government is the recipient of corporate taxes, it is a beneficiary," he said.

With files from Reuters