Heavy rain has pounded Beijing, causing chaos for the capital's air, rail and road transport. Major roads were gripped by gridlock and some subway services were suspended. About 300 flights in and out of Beijing Capital International Airport were also delayed.

The storm rolled in at 4PM on Thursday.

For four hours it lashed Beijing with its heaviest rain this year.

The city received 35 millimeters of precipitation by 5:30 PM. Some major roads were submerged in up to 20 centimeters of water, wreaking havoc for motorists and pedestrians alike.

More than 7,000 traffic police worked to ease the gridlock.

Sun Jisong, Chief Engineer of Beijing Meteological Bureau, said, "Powerful winds, hail and up to 50 millimeters of rain hit some areas. Earlier, we advised people to be prepared for the storm."

Water leaked into the subway along some lines.

The rain also wreaked havoc on subway lines 1, 13, and the Yizhuang line which opened just months ago.

Services were suspended on sections of lines 1 and 13, as some stations experienced minor flooding.

But services resumed on both lines by 8 PM.

Sun said, "The light rains are expected to continue into Thursday night and Friday morning, due to a strong cold front sweeping the region."

The rain also grounded flights at the capital's main airport, where more than 200 flights were delayed or canceled.

Authorities also warned of landslides in Beijing's northern mountainous areas.