By Rafiq Vayani DUBAI: Global superstar Mariah Carey and acclaimed Emirati artist and Expo 2020 Ambassador Hussain Al Jassmi will perform live for the UAE on 20 October 2019, kick-starting the One Year to Go countdown to Expo 2020 Dubai, the World’s Greatest Show. The entire nation is invited to join in free, family-friendly festivities in every emirate from 1700 to 2200, topped off …