Firefighters and volunteers rescue passengers trapped by deep rain waters in Beijing, on July 21, 2012. The heaviest rain in 61 years that lashed Beijing Saturday have left at least four people dead and six others injured, local authorities said. The heavy rain that began to thrash the city around 10 am on Saturday inundated roads, making some impassable, and severely disrupted air traffic.[Photo/Xinhua]

A military training base is trapped by waters before all the 350 students and 40 teaching staff trapped were relocated in the Fangshan District of Beijing, on July 21, 2012. [Photo/Xinhua]

A citizen wades through on a flooded street in Beijing, on July 21, 2012. [Photo by Zhu Xingxin/China Daily]

Cars are submerged in a flooded road in downtown Beijing in the evening on July 21, 2012. [Photo/Xinhua]

Flood control people drain off waters on a flooded road in Beijing in the evening on July 21, 2012. [Photo/Xinhua]

Pedestrians wade through in rain waters carrying a baby carriage in an underground passage near the Beijing West Railway Station, on July 21, 2012. [Photo/Xinhua]