Torrential rain swept through Shanghai on Aug. 25, causing flight delays.

Thunderstorms began at about 6 a.m. in downtown Shanghai, and local weather and flood offices issued numerous warnings of potential hazards, officials said.

An official with the Shanghai Airlines Co. said the downpours affected arriving and departing flights at its two airports -- Hongqiao and Pudong. At Hongqiao alone, a dozen flights were postponed or diverted.

The official added that with the storms persisting, it was very hard to predict when normal operations could resume.

A spokesman at the Shanghai Municipal Weather Observatory said the excessive rain was caused mainly by weather phenomena known as an upper trough and a near-land stationary front.

The remnants of Typhoon Nuri, which made landfall in south China's Guangdong Province late last week, also had an indirect role, said the spokesman.