A woman wearing a mask rides a bicycle amid heavy smog in Beijing, China, November 28, 2015. Heavy smog continues in Beijing on Saturday after a yellow alert of air pollution was issued on Friday, local media reported. Beijing plans to ramp up its already tough car emission standards by 2017 in a bid by one of the world's most polluted cities to improve its often hazardous air quality. (Photo by Jason Lee/Reuters)





Fan Guohui comforts his wife Zheng Qing as they show their son's resting place to reporters on their visit to the graveyard in Zhangjiakou, China, November 22, 2015. Fan Lifeng, the son of Fan Guohui and his wife Zheng Qing, both aged 56, was born in 1984 and died in a car accident in 2012. Fan Guohui has petitioned the government to give financial and moral support to "shidu" parents, those whose only child had died. Zheng Qing said the couple was "emotionally ruined". China scrapping its one-child policy has deepened the sorrow of some parents whose only child has died, in a country where children traditionally look after their parents in old age. (Photo by Kim Kyung-Hoon/Reuters)





Elderly people exercise in a park on a heavily polluted morning in Beijing, China, November 29, 2015. Beijing plans to ramp up its already tough car emission standards by 2017 in a bid by one of the world's most polluted cities to improve its often hazardous air quality. (Photo by Damir Sagolj/Reuters)





Cranes are seen above a construction site amid heavy fog in Xi'an, Shaanxi province, China, November 29, 2015. (Photo by Reuters/Stringer)





Participants Nanjing, Jiangsu province, China, November 29, 2015. More than 1.4 million people signed up for the exam to compete for over 27,000 civil servant positions this year, Xinhua News Agency reported. (Photo by Reuters/Stringer)





An aerial view shows cars passing below a pedestrian overpass in the shape of a circle in Guiyang, Guizhou province, China, November 28, 2015. The 20-year-old overpass, once a landmark of the city of Guiyang, will be demolished on Monday as part of the city's transportation revamp, local media reported. (Photo by Reuters/Stringer)





People exercise as others read newspapers displayed in a park on a heavily polluted morning in Beijing, China, November 29, 2015. Beijing plans to ramp up its already tough car emission standards by 2017 in a bid by one of the world's most polluted cities to improve its often hazardous air quality. (Photo by Damir Sagolj/Reuters)





People walk in a park on a heavily polluted morning in Beijing, China, November 29, 2015. (Photo by Damir Sagolj/Reuters)





People select sheep and goats at a livestock trading market in Yanqi Hui Autonomous County, Xinjiang Uighur Autonomous Region, China, November 29, 2015. (Photo by Reuters/China Daily)





Herders counts yuan banknotes at a livestock trading market in Yanqi Hui Autonomous County, Xinjiang Uighur Autonomous Region, China, November 29, 2015. (Photo by Reuters/China Daily)





A primary school student gets into a minivan as her mother picks her up outside her school, in Beijing, November 25, 2015. Automakers are betting that Chinese families will embrace the mini-van, hoping the larger, unsexy sibling of the bestselling SUV will become the next big thing just as Beijing relaxes the one-child policy. (Photo by Jason Lee/Reuters)





A woman walks past a van which has been converted into a stall selling nail polish on a sidewalk in Beijing, in this June 4, 2013 file photo. (Photo by Barry Huang/Reuters)





A street vendor wears a protective mask on an extremely polluted day in Baoding, China November 30, 2015. Baoding, located in Hebei province neighbouring Beijing was the most polluted city in China in the first half of 2015, according to the country's Ministry of Environmental Protection. (Photo by Damir Sagolj/Reuters)





A woman and a child wear protective mask while riding bicycle on an extremely polluted morning as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





People wear protective masks on an extremely polluted morning as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





Volunteers exercise before delivering free food on an extremely polluted morning as hazardous, choking smog continues to blanket central Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





People wear protective masks while riding a moped on an extremely polluted morning as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





Street vendors prepare food for commuters on an extremely polluted morning as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





A woman wearing a protective mask walks in front of the China Central Television (CCTV) building on an extremely polluted morning as hazardous, choking smog continues to blanket Beijing December 1, 2015. (Photo by Damir Sagolj/Reuters)





Primary school students use their red scarfs to form a giant ribbon to mark the World AIDS Day in Dexing, Jiangxi province, China, November 30, 2015. (Photo by Reuters/China Daily)





A man wearing a protective mask walks as smog covers China's capital Beijing on an extremely polluted day, December 1, 2015. (Photo by Jason Lee/Reuters)





A woman wearing a protective mask walks along a traditional alleyway, or hutong, as smog covers China's capital Beijing on an extremely polluted day, December 1, 2015. (Photo by Jason Lee/Reuters)





A protester wearing a mask stands near the headquarters of Supreme People's Court of China as smog covers China's capital Beijing on an extremely polluted day, December 1, 2015. (Photo by Jason Lee/Reuters)





A woman wearing a mask walks as smog covers China's capital Beijing on an extremely polluted day, December 1, 2015. (Photo by Jason Lee/Reuters)





A man covers his mouth with a scarf along Chang'an Avenue as smog covers China's capital Beijing on an extremely polluted day, December 1, 2015. (Photo by Jason Lee/Reuters)





A man wearing a mask walks through an underground passage as smog covers China's capital Beijing on an extremely polluted day, December 1, 2015. (Photo by Jason Lee/Reuters)





A policeman looks at a car which fell into a pit after crashing through a brick wall, on a hazy day in Xianyang, Shaanxi province, China, November 30, 2015. Local police said the accident occurred in early morning on Monday when the driver could not see the road clearly due to thick fog. No one was injured from the crash, local media reported. (Photo by Reuters/Stringer)





Pedestrians look at a car which fell into a pit after crashing through a brick wall, on a hazy day in Xianyang, Shaanxi province, China, November 30, 2015. (Photo by Reuters/Stringer)





A resident rides an electric bicycleacross a street amid heavy smog as vehicles wait for a traffic light next to a statue of pandas, a landmark of the Wangjing area in Beijing, China, December 1, 2015. (Photo by Reuters/China Daily)





Apartment rooms are lit up with lights during daytime on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Kim Kyung-Hoon/Reuters)





Visitors wearing protective masks take a selfie in front of the National Stadium, also known as the "Bird's Nest", on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Kim Kyung-Hoon/Reuters)





A man pulls his luggage past electronic screens showing the Olympic Green park under blue skies, near the National Stadium (R), or the Bird's Nest, amid heavy smog in Beijing, China, December 1, 2015. (Photo by Reuters/China Daily)





An investor with a face mask looks at a computer screen showing stock information at a brokerage house in Fuyang, Anhui province, China, December 1, 2015. (Photo by Reuters/Stringer)





Parents who lost their only child hold signs as they gather in front of the National Health and Family Planning Commission office in Beijing, China, December 1, 2015. Hundreds of such parents demanded financial and legal support from the government for the loss of their only child, according to participants of the gathering. China, the world's most populous country with nearly 1.4 billion people, says the once-child policy has averted 400 million births since 1980, saving scarce food resources and helping to pull families out of poverty. The signs read "shidu" (bottom R) or those who have lost their only child, as well as the names of towns where the parents come from. (Photo by Kim Kyung-Hoon/Reuters)





Women walk out of the Tiananmen Gate on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





People wear protective masks next to a paramilitary soldier at the Tiananmen Square on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





Policemen wear protective masks behind a paramilitary soldier at the Tiananmen Square on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





Policemen wear protective masks near the Forbidden City on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





A girl wearing a protective mask talks to a policeman near the Forbidden City on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





A couple wearing protective masks take pictures of themselves at the Tiananmen Gate on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





A girl wearing a protective mask waves Chinese flag after visiting the Forbidden City on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





A woman wearing a protective mask talks to policemen, also wearing masks, near the Forbidden City on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





Women wearing traditional clothes have their picture taken atop the Jingshan Park on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





People wearing protective masks have their picture taken near the Tiananmen Gate on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





People leave the Forbidden City on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





A man wearing protective mask takes pictures of the Forbidden City from the top of Jingshan Park on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





People visit the Jingshan Park on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





People wearing protective masks check their phones at the Tiananmen Gate on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





A man exercises at the Jingshan Park on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





A couple wearing protective masks visit the Tiananmen Gate on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





A man checks his phone in front of a paramilitary soldier at the Tiananmen Square on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





Policemen wear protective masks at the Tiananmen Square on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Damir Sagolj/Reuters)





A woman wearing a protective mask rides a bicycle during an extremely polluted night as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. (Photo by Kim Kyung-Hoon/Reuters)





Artist Kong Ning wears a wedding dress made from respirators to highlight concerns about air quality and pollution in Beijing, China on December 1, 2015. (Photo by Luo Xiaoguang/Xinhua Press/Corbis)





Visitors use mobile phones to take pictures and videos as they watch a flag raising ceremony at the Tiananmen Square amid heavy smog in Beijing, China, December 1, 2015. (Photo by Reuters/Stringer)





A Chinese worker wearing a mask on a day of heavy pollution on December 1, 2015 in Beijing, China. China's capital and many cities in the northern part of the country recorded the worst smog of the year with air quality devices in some areas unable to read such high levels of pollutants. Levels of PM 2.5, considered the most hazardous, crossed 600 units in Beijing, nearly 25 times the acceptable standard set by the World Health Organization. The governments of more than 190 countries are meeting in Paris this week to set targets on reducing carbon emissions in an attempt to forge a new global agreement on climate change. (Photo by Lintao Zhang/Getty Images)





A woman selling snacks waits with her bicycle cart outside of a subway station amid heavy pollution and fog in Beijing, Tuesday, December 1, 2015. Schools in the Chinese capital kept students indoors and parents brought their kids to hospitals with breathing ailments today as Beijing grapples with extremely severe air pollution for the fifth straight day. (Photo by Mark Schiefelbein/AP Photo)