Hundreds of kilometres of Dutch highways were clogged with traffic jams on Wednesday when construction workers drove trucks, diggers and cranes to a protest against moves to cut nitrogen pollution that could impact their jobs.
The country's traffic authority ANWB said the traffic jams, centred around The Hague, stretched 380 kms (240 miles). Police said a central protest site in The Hague had been closed to any more large vehicles, but shuttles were still bringing workers.
While many countries have been disrupted by protests against carbon dioxide emissions that worsen climate change, the Netherlands has also faced protests by construction workers and farmers angered by a May court ruling that found the country was emitting too much nitrogen in violation of European law.
Wednesday's demonstration is the fifth in a series that began in September.
The farming and construction industries are the biggest single emitters of the gas, yet many individuals feel they are being unfairly blamed for a problem caused by the whole of Dutch society.
Politicians have suggested that some of the 18,000 building projects around the country could be shelved or face more stringent rules in the future, while some livestock farmers may be offered subsidies to halt their business or limit emissions.