SHANGHAI—More than one in five homes in China's urban areas is vacant, and a current housing-price correction is putting additional pressure on the owners of such empty properties, according to a nationwide survey by researchers from China's Southwestern University of Finance and Economics.

The vacancy rate of sold residential homes in urban areas reached 22.4% in 2013, or 49 million homes, up from 20.6% in 2011, according to the Survey and Research Center for China Household Finance, which conducted the analysis.

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