China Spends $7B on World’s Longest Undersea Tunnel, Flooded in Less Than 2 Years, Built Like Trash

Recently, heavy rain has continued across southern China, causing river levels to rise sharply. Many towns and villages were quickly submerged, with houses flooded. From above, the once-busy city streets disappeared, replaced by muddy floodwaters carrying debris through buildings. On the evening of May 20, 2026, Guangdong province experienced severe rainfall. Some areas of Shenzhen recorded extreme short-term rainfall. The Shenzhen Zhongshan Undersea Tunnel, also called the Shenzhong Link, flooded. It left many vehicles stalled. Videos from the scene spread rapidly online. Drivers reported being trapped for nearly an hour, describing the experience as swimming in the tunnel. Footage shows emergency vehicles, flashing lights, and long lines of stalled cars. Many question how such a large project could fail to manage rainwater effectively. An overseas user on X commented, Chinese infrastructure may be cheap, but its lifespan can be deadly. Another user wrote, A project like the Shenzhong Link is truly alarming. I hope the authorities investigate the risks thoroughly and do not let the safety of citizens become a sacrifice for power. The storm exposed vulnerabilities in this century project. Flooding in a tunnel tens of meters below the sea revealed weaknesses in management and safety, challenging claims of China's construction prowess. Reports state that the Shenzhong Link opened for a trial operation on June 30, 2024. The 24-kilometer route combines bridges, islands, tunnels, and underwater interchanges. The undersea immersed tube section spans about 6.8 kilometers, reportedly the widest eight-lane, two-way undersea tunnel in the world. After seven years of planning and seven years of construction, the project cost around 44.7 billion yuan. Travel time between Shenzhen and Zhongshan shortened by only 30 minutes, raising doubts about its cost-effectiveness. Less than two years after opening, water accumulation has raised concerns about the quality of the so-called century project. The 50 billion yuan investment could have improved local public services, enhanced city drainage systems, and ensured resident safety. Instead, flooding quickly neutralized the tunnel's claim as the world's widest eight-lane undersea tunnel. Reports indicate that Shenzhen traffic police imposed temporary traffic control at the tunnel entrance on May 20 at 9 a.m. All water was cleared by 11 p.m. On May 22, a tunnel engineering professional in Dongguan told media overseas that every tunnel has a drainage system. He said the flooding shows a failure in that system. The tunnel has at least 20 sewage pumps, each with tens of kilowatts of power. Longer tunnels require more pumps. He said this shows there's a problem with the drainage system. The reservoir water level rose, and the pumps didn't start, which indicates routine maintenance is inadequate. The professional also noted, these tunnels are built by large companies, but installation is outsourced. The bidder doesn't work, the worker can't do it, certified teams won't do it, and those who work have no certification. This is the reality. From an engineering perspective, public concern focuses on two points, whether construction meets quality standards, and whether routine maintenance is sufficient. This event is not isolated. At the same time, other cities in Guangdong, including Guangzhou, Shenzhen, Zhuhai, Yangjiang, Huizhou, Zhongshan, Jiangmen, and Shanwei issued red alerts for heavy rain. Bridges in Enping's Najizhen were washed away, and Miaoming's Gaozhou-Dengshui-Jiang bridge was also damaged. Many areas experienced urban flooding, landslides, and building collapses. Parts of Shenzhen recorded over 300 millimeters of rainfall, setting recent records. Such intensity is not unusual in the Pearl River Delta during the summer, but rapid urban expansion and frequent extreme weather have increased pressure on drainage systems. In Enping, heavy rain caused severe flooding, submerging houses and vehicles, and blocking traffic. From the afternoon of May 20, the city implemented a three-stop measure. Classes, work, and transport were suspended. Bridges collapsed in Najizhen, and caution lines were placed around affected areas. Residents in Najizhen reported water levels reaching one meter. They said, we have not seen rainfall like this in decades. Video showed a bridge broken in the middle, with floodwaters rushing through a gap at nearly bridge level, prompting exclamations from bystanders. The bridge was at the center of town. Its collapse greatly affected travel, forcing residents to detour using other bridges. On May 20, Dapu Town in Gaozhou, Maoming, was hit by heavy rain, causing rivers to rise and trigger urban flooding. Video showed Deng Shui Jiang Bridge washed away and closed to traffic. Local resident Mr. Wu said, this bridge is the only rural road connecting our town to the city. Now the bridge is broken, the road is closed, and access is very inconvenient. He added that parts of Dapu Town were severely affected. Floodwaters reached 50 to 60 centimeters inside houses and completely submerged roads. Another witness, Mr. Chen, said he saw the flash flood unfold. The rain was extremely heavy and caused a flash flood. The water rose very fast. He said the flood not only destroyed Deng Shui Jiang Bridge, but also washed away or submerged many local crops. Mr. Chen added that relatives along the bridge sent him videos showing landslides in multiple villages. According to Chinese media, Yangchun in Yangjiang recorded over 1,000 millimeters of rainfall in 24 hours on the evening of May 20. For those unfamiliar with meteorology, the scale of this rainfall may be hard to grasp. Many southern Chinese cities see just over 1,000 millimeters of rain in a full year. Yet in a single day, this town experienced nearly a year's worth of precipitation. Such intensity is extremely rare in South China's weather history. Continuous heavy rain caused rivers in Yangjiang to rise sharply, breaching levees and force water back into the city. Streets were completely submerged, with floodwaters covering roads so thoroughly that it was impossible to tell where the street ended and rivers began. Water depth varied across the city, forming a continuous sheet that trapped vehicles and made normal traffic impossible. Parked cars were partially or fully submerged in muddy water. Many low-rise vehicles were entirely underwater, leaving only rooftops visible. Main roads were completely paralyzed, traffic came to a halt, and vehicles floated quietly in the murky floodwaters. Videos from Yangjiang residents showed homes inundated by floodwaters. Furniture, appliances, and household items were soaked or swept away. Some were floating in the water. Interiors were left completely in disarray. In one video, water in the kitchen reached the height of an adult's leg, yet the resident continued cooking and eating. Preparing food in flood conditions is extremely dangerous, with risks of electrocution, poisoning, and infection. Resident Ms. Tai told Jiamian News that her self-built home began flooding around 2 a.m. on May 21. On the first floor, water reached nearly knee height. As of 8 a.m. on May 22, electricity had not been restored. Many residents said the flooding completely submerged the first floor, leaving the home uninhabitable. They had no choice but to move to the second floor or higher levels for safety. Shops along the old street suffered severe losses. Long-established stores saw goods and equipment soaked or destroyed. Years of hard work was wiped out overnight. The owner of Tongda Stationery on Yuzhou Road said that his shop, about 600 meters from the Sihe River, had water reaching his calves. Paper products were severely damaged. He said around 20 boxes of stock were soaked. The warehouse near the restroom was flooded by river water backing up through the drain. After days of rain, the once-bustling Yangjiang Old Street was deserted. Floodwaters and damaged streets replaced the usual liveliness, leaving a stark contrast to its former prosperity. This round of heavy rain struck forcefully. Beyond Guangdong, Hunan Province was also heavily affected. On May 23, at 8 a.m., the Changsha Meteorological Observatory issued a red alert for heavy rain. All 62 towns in the city received extreme rainfall, with Pingtong Street in Xiangjiang New Area recording 269.5 millimeters, meeting the standard for extreme rain. Hunan's Shimen County recently experienced extreme rainfall and severe flooding, causing heavy damage. Roads, bridges, power lines, and communication networks were destroyed. Many villages were cut off from transportation, electricity, and internet, creating a three-outage situation. Numerous homes were washed away or submerged by mudslides and floodwaters. Some riverside houses flooded up to two or three stories. According to official reports, as of 7.30 p.m. on May 22, six people had died and 15 were missing. I lived my whole life and I've never seen a flood this big. When the water came, I saw cars swaying. I heard people shouting about the rising water, trying to start their cars and drive away. Last night, the water came up so fast, we barely made it out. By the time we got up, the water was already waist deep. The flood rushed into our house. Everything inside was swept away. The house didn't collapse, but it's unlivable now, practically unsafe. The water rose to the second floor instantly. Roads were blocked in sections. There was no electricity, no water, and we had to walk five or six kilometers. When roads like ours are damaged, it's different from other places. In other areas, people might still get through, but our road, it's completely destroyed. It's like a knife cut through. On the sides are cliffs, so we can't pass. That's why everyone has to walk. Right now, there are too many villagers escaping on foot. The entire street is underwater. When we'll help arrive, we've been trapped here all night. No way out, no water, no power, nothing to eat or drink. These cars are even blocking our doors. Everything we had is gone. This was our home. And then the rain got heavier. There's a home we can't return to, a home we can't live in. The most valuable thing at home was this electric scooter. We couldn't let it get soaked. As soon as the water receded, we called a few neighbors to move it to higher ground. The rain hasn't stopped for days. We don't know if it will rise again, so we can't leave it at home. This was my factory, my entire livelihood. I invested everything. Now it's all gone, completely submerged. I feel so helpless. Video shows several townships in Ximen County, Changde City, Hunan, under floodwater. At Suojie School in the city's northwest mountains, water has reached the third floor. Residents from Ximen Town posted on social media, family members in my village are missing. We don't know if they're alive. Even if they were not swept away or buried by mudslides, they're enduring freezing rain on the mountain. I don't know how they will survive. They added, some villagers were nearly swept away. They grabbed onto plants and climbed the mountain in the rain, barely surviving. Several landslides occurred across the village. So far, one death has been confirmed, and eight people remain missing, including a three-year-old child. Houses along the river were either destroyed, badly damaged, or buried by mudslides. The severity of the disaster in Jinghe Village, Ximen Town, is largely unknown outside the area. Residents are relying entirely on their own efforts to survive. Under current governance, ordinary people appear helpless in the face of such destructive floods. Many provinces in China have entered the flood season, and southern regions have been hit by heavy rain. The scale of the disaster is largely concealed, and casualties are underreported. These conditions worsen the impact and can trigger secondary disasters. When the rain subsides, widespread destruction remains. Countless families lose years of effort, and for many in China's lower-income communities, a single night of flooding can wipe out their livelihood. Videos show thousands of cars submerged in mud-laden water. Urban infrastructure has proven vulnerable to natural disasters, and resident savings and assets were washed away overnight. These scenes, though not new, continue a pattern and serve as a warning for the future. In an era of collapsed homes and financial turmoil, ordinary people's fate is like silt in turbulent waters. They are swept away with no control, sinking into an uncertain abyss. Faced with recurring whole-city flooding, people have realized that this is not only a natural disaster, but also a recurring man-made problem. Fragile urban drainage and ineffective flood control projects reveal long-standing governance failures. Each flood leaves ordinary vulnerable residents to bear the greatest cost. Authorities continue to blame natural disasters while ignoring the safety of citizens and their property. Emergency responses are often temporary measures for show, and official concern remains largely rhetorical. Behind these disasters lies systemic indifference, long-term neglect of public safety, and deep-rooted flaws in the power structure. Each disaster becomes another hardship imposed on the most vulnerable, while the label of natural disaster obscures human responsibility.