From the Los Angeles Times (link):
Since China’s economic boom helped boost its international standing and national confidence, the country has begun a quest to reclaim art and relics lost or stolen during decades of foreign domination and occupation. Zhoukoudian officials believe that finding the fossils will allow scientists to undertake additional study and help their community’s image.
Calls for a new search arose among Chinese scholars in the late 1990s. Chinese journalists in 2000 published a manifesto linking the rediscovery of the fossils to restoring China’s national pride.