By Donny Kwok and Jessie Pang HONG KONG (Reuters) -Blackened skies unleashed torrential rains on Hong Kong and the high-tech cities surrounding south China's Pearl River Delta on Tuesday, shutting hospitals,

Hong Kong came to a standstill on Tuesday as torrential rain pounded the city for the second time in less than six hours, triggering a rare black rainstorm warning, paralysing public services and flooding key urban districts.

Parts of Hong Kong were brought to a standstill by flooding caused by heavy rains on Tuesday, after the highest-tier rainstorm warning was issued for the fourth time in eight days.Neighbouring Chinese tech hub Shenzhen issued a "red" rainstorm warning earlier in the day,