Hong Kong has seen the biggest uptick in cryptocurrency activity in East Asia amid the city's efforts to become a virtual-asset hub, according to new research, while mainland Chinese use digital currencies to preserve wealth in spite of the government's draconian ban. The city rose to 30th place, up from the No 47 spot last year, in this year's Global Cryptocurrency Adoption Index rankings published on Wednesday by research firm Chainalysis. It said Hong Kong saw an 85.6 per cent year-on-year su