Police officers talk to people gathered to protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. Protesters wearing masks gave out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

A protester wears a mask with a reference to the chemical paraxylene, during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. Protesters wearing masks gave out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

A protester wears a mask with a reference to the chemical paraxylene, during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. Protesters wearing masks gave out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

A protester wears a mask with a reference to the chemical paraxylene, during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. Protesters wearing masks gave out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

A protester wears a mask with a reference to the chemical paraxylene, during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest. Protesters wearing masks gave out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

Protesters shout slogans behind a line of police officers during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest. Protesters wearing masks gave out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

Police officers arrest a protester during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. Protesters wearing masks gave out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

A protester wears a mask which reads "not PX", in reference to the chemical paraxylene, during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. Protesters wearing masks gave out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

A riot police officer argues with protester during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. Protesters wearing masks gave out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

A protester shouts slogans during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. Protesters, watched over by police, gathered on a central shopping street, wearing masks and giving out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

A protester stands next to police officers as she wears a mask which reads "PX no way", in reference to the chemical paraxylene during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. Protesters, watched over by police, gathered on a central shopping street, wearing masks and giving out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

Police officers arrest a protester during a protest against plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. Protesters, watched over by police, gathered on a central shopping street, wearing masks and giving out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. Protesters said that the chemical paraxylene was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST BUSINESS) 

Riot police arrest a protester during a protest against the plans to expand a petrochemical plant in Ningbo, Zhejiang province October 27, 2012. More than a thousand people gathered in the eastern Chinese port city of Ningbo on Saturday for the protest, highlighting a major challenge for the leadership as it readies for its once-in-a-decade power transition. By early Saturday, protesters, watched over by police, gathered in a central shopping street in Ningbo, wearing masks and giving out pamphlets denouncing the expansion of the plant by a subsidiary of China Petroleum and Chemical Corporation in the district of Zhenhai. "PX...Get out of Ningbo!" read one placard, in a reference to the chemical paraxylene, which the protesters said was a carcinogen. REUTERS/Carlos Barria (CHINA - Tags: CIVIL UNREST ENVIRONMENT TPX IMAGES OF THE DAY BUSINESS) 

The company logo of Sinopec is displayed at a news conference in Hong Kong March 30, 2009. Top Asian oil refiner Sinopec Corp said on Monday its overseas acquisitions will focus on Africa and South America. REUTERS/Bobby Yip (CHINA BUSINESS ENERGY) 

The company logo of Sinopec Corp is displayed at a gas station in Hong Kong August 26, 2008. Top Asian oil refiner Sinopec Corp posted an 87 percent fall in quarterly earnings as soaring crude prices and caps on state-set fuel prices pushed its refining business into the red, despite government subsidies. REUTERS/Bobby Yip (CHINA) 

Workers walk inside China National Petroleum Corporation (CNPC) Lanzhou Chemical Company in Lanzhou, capital of northwest China's Gansu province April 27, 2007. REUTERS/Jason Lee (CHINA) 

A worker cycles inside China National Petroleum Corporation (CNPC) Lanzhou Chemical Company in Lanzhou, capital of northwest China's Gansu province April 27,2007. REUTERS/Jason Lee (CHINA) 

A worker checks equipment inside China National Petroleum Corporation (CNPC) Lanzhou Chemical Company in Lanzhou, capital of northwest China's Gansu province April 27,2007. REUTERS/Jason Lee (CHINA) 

A worker walks inside China National Petroleum Corporation (CNPC) Lanzhou Chemical Company in Lanzhou, capital of northwest China's Gansu province April 27,2007. REUTERS/Jason Lee (CHINA) 

Employees take part in a rope skipping competition during a midday break outside the China National Petroleum Corporation (CNPC) Lanzhou Chemical Company in Lanzhou, capital of northwest China's Gansu province April 27, 2007. REUTERS/Jason Lee (CHINA) 

Employees take part in a rope skipping competition during a midday break outside the China National Petroleum Corporation (CNPC) Lanzhou Chemical Company in Lanzhou, capital of northwest China's Gansu province April 27, 2007. REUTERS/Jason Lee (CHINA) 

Employees take part in a rope skipping competition during a midday break outside the China National Petroleum Corporation (CNPC) Lanzhou Chemical Company in Lanzhou, capital of northwest China's Gansu province April 27, 2007. REUTERS/Jason Lee (CHINA)