A severe rainstorm on the night of 10 September 2026 caused the HC1‑02 flood tunnel at the An Phú interchange in Ho Chi Minh City to become inundated with up to half a metre of water over a 300‑metre stretch. The tunnel, 480 m long, 14 m wide and equipped with four traffic lanes, is a key link between the Mai Chí Thọ avenue and the TP HCM‑Long Thành‑Dầu Giây highway. The flood, the first of its kind since the tunnel opened to traffic on 2 February 2026, forced the Ban Quản lý dự án đầu tư xây dựng các công trình giao thông TP.HCM (Ban Giao thông) to close both directions and divert vehicles onto surface roads, creating a congestion belt of more than 2 km around the interchange.
In response, the Ban Giao thông coordinated with the fire‑police rescue unit, the City’s urban drainage company and over ten staff members to deploy large‑capacity pumps operating at full power. Temporary pump stations, currently delivering about 70‑80 % of the design capacity, were used while the permanent three‑pump system—still under construction—was slated for completion within roughly 15 days. Additional pumps were brought to the site on the afternoon of 11 September, and temporary dikes were erected to limit further inflow from the surrounding roads.
By 13:00–13:45 on 11 September, water levels had receded sufficiently for the tunnel to reopen to traffic in both directions, with only light surface water remaining. The reopening restored the normal flow of vehicles between the highway and Mai Chí Thọ, easing the earlier bottleneck. Officials indicated that the incident highlighted the need for enhanced drainage capacity at major underground links, and that the forthcoming permanent pump installation will improve resilience against future heavy‑rain events.