(250617) -- CHONGQING, June 17, 2025 (Xinhua) -- Rescuers are pictured at the entrance of the high-speed railway tunnel under construction where a carbon monoxide leak occurred in southwest China's Chongqing Municipality, June 17, 2025. Seven people were trapped following a carbon monoxide leak in a high-speed railway tunnel under construction in southwest China's Chongqing Municipality Tuesday afternoon, local authorities said. Four people have been rescued and three remain trapped. The incident occurred in the Zhongliangshan tunnel, part of the Chongqing section of the Xi'an-Chongqing high-speed railway. Rescue efforts are underway. (Xinhua/Chen Cheng)