US report says China's war on pollution is being lost at ports

China is waging war on pollution, closing factories and targeting dirty coal-fired power plants, but its ports are pumping out pollution virtually unchecked, according to a report by a US environmental group.

The thousands of ships that plied China's waters were delivering a toxic cocktail of pollution, with just one ship capable of emitting the same pollution as half a million trucks each day, the report by the Natural Resources Defence Council (NRDC) said.

"China is paying a high price for pollution associated with shipping," it said, citing studies in Hong Kong and Shenzhen.

"An estimated 1.2 million premature deaths in China in 2010 were caused by ambient air pollution, and shipping is a significant source of these air-pollution and health problems."

Seven of the 10 biggest ports are in China, with more than a quarter of the planet's maritime cargo passing through the country. Coastal cities like Guangzhou, Shanghai and Shenzhen are among the most polluted.

Hong Kong has suffered the most from such emissions in the Pearl River Delta, with city residents accounting for 75 per cent of deaths related to sulphur dioxide released from vessels, a think tank found in 2012. Air quality at Kwai Chung and Tsim Sha Tsui was likely to be worst affected by pollution from ships, a five-year study by Civic Exchange found.

The NRDC report said: "With ocean-going ships allowed to burn fuel with sulphur levels that are 100 to 3,500 times higher than permitted in on-road diesel, one container ship cruising along the coast of China emits as much diesel pollution as 500,000 new Chinese trucks in a single day."