From the U.S. DEPARTMENT OF STATE OVERSEAS SECURITY ADVISORY COUNCIL

Multiple survey respondents identified China as their travel destination
when they discovered their mobile phone had been hacked. This commonly led
to disappearing apps, and disruption to the phone's primary communications
functions. China has been identified as a high risk location for mobile
malware, mobile device privacy attacks, and a hot spot for mobile botnets.

Read more: http://docs.apwg.org/reports/mobile/APWG_Mobile_Report_v1.9.pdf