AI surveillance on Seoul's Han River bridges saves lives as South Korea battles suicide crisis

Seoul's Han River is beautiful and terrible at once. The waterway cuts through South Korea's gleaming capital, a landmark of prosperity and modernity. It is also where despair regularly surfaces. For years, the river has been a frequent destination for people in crisis, a fact that sits uneasily beneath the city's polished surface.

In 2021, the city installed a network of nearly 900 AI-powered cameras across 17 bridges spanning the Han. The system works with a specific logic: artificial intelligence watches for patterns of danger. Someone lingering too long in a particular spot. A person entering an area flagged as high-risk. Someone picking up one of the dedicated suicide-prevention phones mounted on the railings. When the algorithm detects these signs, it alerts first responders immediately. The window is narrow—most emergency crews can reach a bridge within five minutes, the critical span in which intervention becomes possible.

The results have been stark. In 2012, before the system existed, rescue crews saved 56 percent of people they reached on the Han River bridges. Today, that figure stands above 99 percent. Last year alone, the cameras identified more than 1,200 incidents across the 17 bridges. Of those, approximately eight people could not be saved despite the rapid response. Kim Jun-young, who leads the Hangang Bridge CCTV Integrated Control Center, describes the work plainly: "We see our role as giving them one more chance to think it over, because it may not be the decision you want." He notes that from a height of 30 meters, the impact with water approximates a car crash at 60 kilometers per hour. Some people who reach the railing change their minds when they hear sirens approaching. Others fight rescuers or run, as if competing in a sprint. The system has become, in effect, a technological intervention in the final seconds of a person's deliberation.

Yet the cameras exist within a much larger crisis. South Korea has one of the world's highest suicide rates. In 2024, the rate climbed above 29 deaths per 100,000 people—the highest since 2011. More than 40 people die by suicide each day in the country. For people aged 10 to 49, suicide is the leading cause of death. President Lee Jae Myung has called the crisis "a disgrace on the world stage." The drivers are structural and cultural: relentless academic pressure, demanding work schedules, a social environment that holds individuals responsible for their failures, and deep stigma around seeking mental health support. Yoo Jae-hyun, director of suicide prevention at Seoul St. Mary's Hospital, has heard the same refrain from many patients who attempted to end their lives: they felt they had become a burden to those around them, that everyone else would be better off without them. Young adults in their twenties make up the largest share of people treated in emergency rooms after suicide attempts.

Smiling Stone Hwang, a 33-year-old cartoonist, was rescued by first responders after her own attempt. Her story illuminates the weight that precedes such moments. In 2014, her father died by suicide. He had struggled with alcohol addiction for years, though he had once been a successful film producer with a deep passion for cinema. Shortly before his death, he visited the cafe where Hwang worked, bringing her a gift. The cafe was unusually crowded that day, and she never got to buy him a coffee. After his death, she inherited his debts and faced years of lawsuits and asset seizures that left her unable to hold a bank account in her own name. Throughout her twenties, she worked multiple cash-paying jobs, often for grueling hours. When she contemplated suicide, it did not feel tragic to her. It felt rational. "Being accepted for who I am" has helped her since then, she told reporters. In her cartoon-based memoir, "I Am a Suicide Loss Survivor," she wrote about returning daily to the cafe after his death, leaving a cup of coffee at the cramped table where he never got to sit. "One he could never drink again, and one I could never brew for him again."

Other countries are experimenting with similar technological approaches. A Japanese company called Asilla has developed AI surveillance systems that detect unusual behavior—falls, or someone preparing to jump from a height—by learning patterns from cameras in public spaces like shopping centers and train stations. In two separate incidents, the system alerted guards to men standing on rooftops who were then talked down. But Yuka Suzuki, the company's chief product officer, is careful about what the technology can and cannot do. "It's still often difficult to provide proper mental health support," she said. The AI is not meant to replace human intervention or solve a suicide crisis on its own. What matters, she suggested, is whether the system can "reduce the number of incidents, even by a little, where people lose their lives in the blink of an eye."

Back in Seoul, Kim recalled a case that illustrates the limits of even a 99 percent rescue rate. A young man was intercepted by the AI system and emergency workers, who brought him to safety. He returned to the same bridge later that day. While smoking with a friend, he made another attempt. Despite rescuers and a boat already positioned in the water, they could not save him. The cameras had worked. The system had responded. The human crisis remained.