File photo taken on May 3, 2011 shows trolley buses in Hong Kong, south China. Hong Kong's public transportation system, consisted of subway, buses, minibuses, trolleys and ferries, is well known for its efficiency and it undertakes 90 percent of people's daily trips. July 1, 2012 marks the 15th anniversary of the establishment of the Hong Kong Special Administrative Region (HKSAR). (Xinhua)
