Carrying permits demanding “fast passage,” truck drivers rushed a 560-ton shipment of disinfectant from eastern China to Wuhan, the locked-down city of 11 million people at the center of a vast effort to contain a new viral disease.

Outside the metropolis in central China, the cargo was shifted to local trucks with drivers in masks and protective suits, part of a tightly controlled flow of food and other supplies through checkpoints that have blocked most access to Wuhan since Jan. 23.

As global anxiety about the new virus rises, authorities have blocked 50 million people from leaving Wuhan and nearby cities at the center of the outbreak. That in turn requires a massive effort to keep them supplied with food and other necessities.

“Wuhan is not an isolated island,” declared a state newspaper, the Yangtze Daily.