Shanghai's skyscrapers Shanghai World Financial Center (L), Shanghai Tower (R) and Jin Mao Tower (top) are seen at the financial district of Pudong during Earth Hour in Shanghai March 29, 2014. Earth Hour, when everyone around the world is asked to turn off lights for an hour from 8.30 p.m. local time, is meant as a show of support for tougher action to confront climate change. REUTERS/Carlos Barria (CHINA - Tags: SOCIETY BUSINESS TPX IMAGES OF THE DAY) 

A man does pull-ups as part of his morning exercise on a hazy day in Hefei, Anhui province March 30, 2014. China's plan for a market in air pollution permits promises to help clean up its air cheaply, but the move could prove just as useless as previous environmental policies unless the government stamps out lax enforcement and spotty data. REUTERS/Stringer (CHINA - Tags: ENVIRONMENT HEALTH) 

A tricycle travels past a crossroad on a hazy day in Hefei, Anhui province March 30, 2014. China's plan for a market in air pollution permits promises to help clean up its air cheaply, but the move could prove just as useless as previous environmental policies unless the government stamps out lax enforcement and spotty data. REUTERS/Stringer (CHINA - Tags: ENVIRONMENT TRANSPORT TPX IMAGES OF THE DAY) 

People wearing masks walk in front of the statue of late Chinese leader Mao Zedong in a university, during a hazy day in downtown Shanghai December 26, 2013. China is struggling to meet its 2011-2015 targets to reduce pollution, cut greenhouse gas growth and introduce cleaner sources of energy, a report submitted to the country's parliament said on Wednesday. REUTERS/Aly Song (CHINA - Tags: POLITICS ENERGY ENVIRONMENT SOCIETY EDUCATION TPX IMAGES OF THE DAY) 

The financial district of Pudong is seen on a hazy day in Shanghai January 21, 2013. Beijing is to unveil unprecedented new rules governing how China's capital reacts to hazardous air pollution, the official Xinhua news agency said, as deteriorating air quality threatens to become a rallying point for wider political dissatisfaction. REUTERS/Aly Song (CHINA - Tags: ENVIRONMENT POLITICS TPX IMAGES OF THE DAY) 

A tourist boat, decorated with green lights, travels on the Pearl River amid heavy haze in Guangzhou, Guangdong province March 3, 2014. China's environment ministry has vowed to 'harshly punish' factories and power plants that contributed to a hazardous smog which enveloped much of Northern China, official state media reported. REUTERS/Alex Lee (CHINA - Tags: ENVIRONMENT TRANSPORT POLITICS TPX IMAGES OF THE DAY) 

Cars drive on the Three Ring Road amid the heavy haze in Beijing February 26, 2014. China's north is suffering a pollution crisis, with the capital Beijing itself shrouded in acrid smog. Authorities have introduced anti-pollution policies and often pledged to clean up the environment but the problem has not eased. REUTERS/Jason Lee (CHINA - Tags: ENVIRONMENT BUSINESS) 

A group of expatriates walk along the Bund as they distribute face masks to pedestrians to raise awareness of air pollution in downtown Shanghai January 24, 2013. REUTERS/Carlos Barria 

Paramilitary policemen practise drills inside the Forbidden City during a heavy haze and smog night in central Beijing December 4, 2011. China's air pollution standards are too lax, a senior environment official said in comments published earlier this month, the highest level comment following complaints that authorities are understating the extent of smog that often envelops Beijing. REUTERS/Jason Lee (CHINA - Tags: ENVIRONMENT TRAVEL TPX IMAGES OF THE DAY) 

A statue of China's late Chairman Mao Zedong is seen in front of buildings during a hazy day in Shenyang, Liaoning province, May 7, 2013. REUTERS/Stringer (CHINA - Tags: POLITICS ENVIRONMENT TPX IMAGES OF THE DAY) 

Vehicles drive on the Third Ring Road on a very hazy winter day in Beijing January 12, 2013. Microscopic pollutant particles in the air have killed some 8,600 people prematurely in 2012 and cost $1 billion in economic losses in four Chinese cities, according to a study by Beijing University and Greenpeace. The study of pollutant levels of PM2.5, or particles smaller than 2.5 micrometres in diameter, in Beijing, Shanghai, Guangzhou and Xi'an called for PM2.5 levels to be cut to World Health Organisation guidelines, which would reduce deaths by over 80 percent, the China Daily newspaper reported. REUTERS/Jason Lee (CHINA - Tags: ENVIRONMENT TRANSPORT TPX IMAGES OF THE DAY)