Senior citizens dance during a gathering for the upcoming Chongyang Festival, a traditional day celebrating the elderly on the ninth day of the ninth month according to the lunar calendar, in Nanjing, East China's Jiangsu Province, October 15, 2007. China's aging population is growing rapidly, with seniors expected to account for 30 percent of the Chinese population in 2050, according to figures from the United Nations Population Fund. [Xinhua]