Blackened skies unleashed record-breaking rains on Hong Kong and the high-tech cities surrounding South China's Pearl River Delta on Tuesday, disrupting hospitals and shuttering schools and law courts across the Asian financial hub.

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.

Heavy flooding and a city-wide red alert were issued by Hong Kong Observatory. Experts warn of increased landslide risks due to saturated soil from recent storms. Shenzhen also issued a red alert, reflecting regional extreme weather trends.