BANGKOK, Thailand — Bangkok authorities have initiated emergency evacuations and shut down a major thoroughfare after a significant water leak was discovered in the underground Purple Line tunnel in the Klong San district. The incident, which occurred 30 meters below ground near the Wong Wian Yai intersection, has raised immediate public safety concerns and severely disrupted local transit.

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Klong San District Chief Sorasit Lueangroongkiat ordered the immediate suspension of use for buildings situated directly above the leakage site on Thursday night. The infiltration of water into the subway tunnel beneath the Wong Wian Yai roundabout and the adjacent Prachathipok Road has reportedly caused damage to both the tunnel structure and surrounding infrastructure. To mitigate further risks, the district chief mandated the closures and urged the Mass Rapid Transit Authority of Thailand (MRTA), the owner of the Purple Line project, to provide temporary shelters for the displaced residents.

Bangkok Governor Chadchart Sittipunt revealed that the compromised section of the Purple Line tunnel is the exact same location linked to a massive sinkhole that formed on Sam Sen Road in the Dusit district last year. In this latest incident, water breached the lowest section of the tunnel, leading to soil subsidence that is now impacting the structural integrity of nearby buildings. In response, the Bangkok Metropolitan Administration (BMA) and the MRTA have deployed teams to closely monitor water leakage rates, soil levels, and the structural conditions of all buildings within a 30-meter radius of the breach.

Traffic has been fully closed between Ban Khaek Intersection and #WongwianYai after groundwater leaked into the southern Purple Line #MRT construction site. Engineers are pumping out water, sealing the leak and inspecting nearby buildings, while authorities say the situation… pic.twitter.com/yeUCbRWuwp

— Khaosod English (@KhaosodEnglish) July 9, 2026

To prevent further structural damage caused by traffic-induced vibrations, Prachathipok Road has been completely closed to all vehicular traffic between the Wong Wian Yai and Ban Khaek intersections. The Department of Disaster Prevention and Mitigation has broadcasted emergency alerts to residents in the affected districts, advising commuters to utilize Isaraparp and Lat Ya roads as detours or to switch to the BTS elevated railway system. Concurrently, the Bangkok Mass Transit Authority (BMTA) has rerouted and adjusted five bus lines that normally service the closed corridor to accommodate the sudden change in traffic flow.

Footage released by the MRTA illustrates the severe scale of the subterranean flooding, showing sections of the Purple Line tunnel partially submerged with water reaching neck-deep levels in certain areas. Engineering crews are now working urgently to assess the extent of the damage and formulate a comprehensive repair strategy to stabilize the tunnel and prevent further ground subsidence.

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As engineers work to stabilize the subterranean infrastructure, city officials remain on high alert to ensure the safety of the surrounding community and transit users.

-Thailand News (TN)