More than 4,000 people have been left stranded at airports after nearly 50 flights were cancelled today in China's southwest Sichuan Province due to a severe rainstorm, authorities said. A total of 21 flights landed at alternative airports in Chongqing, Kunming, Xi'an, Guiyang and Mianyang today, while another 48 were cancelled. One flight had to return after taking off. Yesterday, 357 flights were delayed, leaving more than 9,000 passengers stranded. About 4,000 people stayed overnight at hotels near airports, according to airport officials. In a separate incident, a landslide triggered by continuous heavy rain damaged parts of a major rail line, linking south-west China's Sichuan and Guizhou provinces, rail authorities said today. The damage took place in Tongzi county, Zunyi city of Guizhou, cutting off the line between Sanyuanba and Mengdu stations. No casualties have been reported so far. About 1,000 emergency workers are repairing the damaged stretch of 40 meters. An area of more than 500 square meters on and around the tracks was covered in mud and stone. Nearly 20 trains have made detours, returned or been canceled in response to the emergency, authorities said. There is a forecast on the website of National Meteorological Center of heavy rain continuing in the provinces of Sichuan, Hubei, Guizhou, Hunan, Zhejiang, Jiangxi and Fujian from today to tomorrow, with precipitation expected to reach up to 90 millimeters. Also,a hydropower station in Changyang County of Hubei Province was temporarily submerged in floods caused by rain. No casualties have been reported so far but traffic and telecom services have been interrupted, state-run Xinhua news agency reported. Heavy rain battered the county last afternoon, causing flooding of the Danshui River. Maximum rainfall reached 228 millimeters in Weijiazhou village. Bridges and roads along the river were damaged. Electricity in Changyang was also cut. Emergency workers rushed to the area. China renewed a blue alert for rainstorms today as the torrential rain that had lashed much of the south showed little signs of weakening. China has a four-tier color-coded warning system for severe weather conditions, with red being the most serious, followed by orange, yellow and blue.