The index assessed sustainability in 112 cities by looking at 18 environmental indicators — from air pollution to waste recycling to mass transit — for the years 2004-2008.

该指数通过观察2004-2008年的18项环境指标评估112座城市的可持续性，这些指标包括空气污染、污水回收利用、公共交通等。

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Meanwhile, us retail giant Walmart has launched a "sustainability index", which by 2013 should give details of the total environmental costs associated with various products.

同时，美国零售业巨头沃尔玛着手进行“可持续性索引(sustainability index)”，在2013年将实现提供各种产品的环境成本。

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Oman is ranked 110 out of 132 nations surveyed in environmental sustainability over the past decade, according to Yale University's 2012 Environmental Performance Index.

CNN: STORY HIGHLIGHTS