On the morning of May 17, 2026, Busan’s Naeseong Underpass—a critical gateway for the city’s traffic—was suddenly closed off following urgent reports of road subsidence. The disruption, which unfolded just after 8:28 AM, quickly snowballed into a major headache for residents, commuters, and city officials alike, as traffic ground to a halt and the specter of repeated infrastructure woes loomed large once again over South Korea’s bustling port city.
According to Newsis, the city authorities received a citizen report about the road surface appearing to sink near the underpass. By 9:18 AM, police and city officials had moved to impose emergency traffic controls, shutting down two lanes in the Myeongnyun direction and one in the Gyodae direction. The resulting chaos was immediate and severe, with congestion rippling through the Dongnae District for nearly ten hours. As one taxi driver, Kim Seyong, told KNN, “It’s really sunken in. The cars are jammed up. Because of this... when the roads are blocked on the weekend, it’s really inconvenient.”
This wasn’t the first time for such trouble at this very spot. Just over a month earlier, on April 5, 2026, the same stretch of road had experienced multiple subsidence points—four at Naeseong Underpass and two more at the nearby Suyeong Riverside Underpass. That incident, too, had triggered large-scale repair work and left many locals frustrated. In fact, since the February opening of the Mandeok-Centum deep tunnel (or "urban expressway"), which runs beneath these roads and was constructed by GS Construction, complaints and reports of uneven surfaces and minor collapses have become routine, as noted by Donga Ilbo.
On May 16, just a day before the latest episode, a pothole had also appeared near the Suyeong Riverside Underpass, prompting yet another round of emergency repairs. Both of these trouble spots share a common denominator: they sit atop or adjacent to the path of the Mandeok-Centum tunnel, a major infrastructure project by GS Construction that has, in the eyes of many, become synonymous with recurring ground instability.
For residents and daily commuters, the repeated closures and repairs are more than just a minor nuisance. “Every morning during rush hour, it’s always blocked,” lamented Park Yongju, a resident of Oncheon-dong, in an interview with KNN. “I think we really need some alternatives.” On May 17, the city’s main arteries were again paralyzed, with drivers forced to detour or simply wait out the jams as repair crews worked against the clock.
The city’s response was swift but familiar. By 12:30 PM, emergency repair crews had begun work on a 730-square-meter stretch of the affected area, focusing on restoring the flatness of the road surface across two 60-meter lanes. According to Newsis, the city managed to reopen traffic in the Myeongnyun direction by 5 PM, and by 7 PM, all lanes were back in service. Yet, the ten-hour ordeal left a bitter taste and renewed questions about the underlying causes of these persistent problems.
City officials and GS Construction have repeatedly emphasized that the subsidence does not pose a safety risk and is, in their words, a “normal part of the ground stabilization process.” As Kim Eunyoung, a team leader at the Busan City Construction Headquarters, told KNN, “There’s no safety issue, but there may be some minor inconvenience while driving. Of course, Busan City is doing everything to improve citizen services.” The city has also been keen to downplay fears of a catastrophic sinkhole. Kim Hyosuk, head of the city’s construction division, explained to Donga Ilbo, “Today, too, we saw a slight lowering of the road in some spots, so we removed the old pavement and repaved it. This isn’t a sudden collapse like a sinkhole, so there’s no need for large-scale backfilling.”
After the April incidents, the city conducted a two-week ground-penetrating radar (GPR) survey to check for underground voids or cavities that might explain the recurring subsidence. The results, reported by both Newsis and Donga Ilbo, found no evidence of hidden underground spaces. Despite this, the city has promised to continue monitoring the area closely and to step up its management efforts to minimize future inconvenience. As one city official summarized to Newsis, “We will continue to strengthen monitoring and management to minimize inconvenience for citizens.”
Still, the explanations have done little to quell public unease. The repeated nature of the incidents—occurring just weeks apart—has left many questioning both the quality of the original construction and the adequacy of the repair work. GS Construction, for its part, has faced scrutiny over allegations of shoddy backfilling practices during the tunnel’s construction. The company has responded by stating that the current issues are simply an extension of the initial stabilization process and that there is no cause for alarm. Yet, as KNN noted, the cycle of repair and disruption seems likely to continue, with further major repaving work already on the horizon.
Adding to the day’s woes, other unrelated incidents underscored the challenges facing city infrastructure and emergency response. In Chungnam’s Asan, 500 liters of diesel spilled onto a roadway, shutting down traffic for three hours as crews worked to clean up the mess, according to YTN. And in a tragic turn, a fire at a goat farm claimed the lives of 200 animals and left the owner injured.
For Busan, however, the focus remains squarely on the Naeseong Underpass and the broader Mandeok-Centum corridor. The city has pledged to complete any additional repair work before the Monday morning commute, hoping to minimize disruption. But with memories of recent closures still fresh and the threat of further subsidence ever-present, many residents remain skeptical. The underlying causes may still be murky, but the impact on daily life is crystal clear—a reminder that even in a city famed for its rapid development, the ground beneath can sometimes prove unexpectedly unsteady.