A high-speed train arrives in Beijing after a five-hour, 800-kilometer journey from Shanghai. The photograph, taken by a photographer at Beijing South Railway Station, shows dirt collected on the train's body from heavy pollution in east-central China.
Grime from air pollution covers the train's exterior.
High-speed trains pass one another at speeds between 200-300 kilometers per hour, causing increased air pressure around the vehicles.
Raised air pressure pushes fine airborne particles onto the train's body, marring its smooth white exterior.