Footage of clashes in France show a demonstrator throwing a rock at a police officer, who then throws it back at him.
What's the optimum driving speed? Can you rely on jerry cans? Plus real-time information on how low fuel has got at French petrol stations.
Dozens of flights have been cancelled as air traffic controllers join the strike action in France.
The UK government warns people travelling to France that strikers blockading oil refineries have caused some stations to be without petrol.