HOUSTON, March 13 (Xinhua) -- The U.S. state of Texas, rich in oil and gas, remains the biggest carbon dioxide emitter in the country, though clean energy policies adopted in recent years have reduced carbon pollution, said a report released on Thursday.
In 2011, the state pumped out 680 million metric tons of greenhouse gases, almost double its closest competitor California, according to the latest available figure quoted in the report from the U.S. Environmental Protection Agency (EPA).
Researchers estimated that carbon dioxide emissions in Texas were down by 18.1 million metric tons in 2012 due to state and federal policies, including renewable fuel standards and tax credits for wind and solar farms.
The clean energy policies have reduced 162 million metric tons of carbon dioxide emissions throughout the United States, the report said, adding that the emissions have declined 12 percent between 2005 and 2012.
Texas was followed by California, Pennsylvania, Ohio, and Florida on a list of carbon dioxide emissions caused by human activities in U.S. states, according to the EPA's data in 2011.