THE HAGUE (Reuters) - Police in the Dutch city of The Hague closed its central parliament square on Wednesday to keep out farmers protesting over what they see as attempts to blame them for nitrogen pollution.
Thousands of irate farmers had driven tractors to The Hague hours earlier in their third large protest in a matter of weeks.
Tractor convoys set out in the early morning, first for the city of Utrecht and later to The Hague, causing long traffic jams across the Netherlands. More than 375 km (233 miles) of roads were blocked, drivers organization ANWB said.
In The Hague, farmers defied orders to limit their protest to designated areas, driving their tractors into the city center despite being told to park them on the outskirts of town and use available buses to reach their planned rally venue.
Authorities had earlier called in the army's support to place large vehicles across several roads to block main routes to the Binnenhof - the seat of the Dutch parliament.
The farmers' original plan had been to occupy the Binnenhof with their tractors, but authorities declared the square off-limits.
The farmers launched their campaign after a court ruling in May found the Netherlands in violation of European emission rules.
Livestock farming is a leading cause of nitrogen pollution, along with construction and transportation. But farmers argue they have made substantial efforts to cut emissions and their role in providing food for the nation is under-appreciated.
"Last year you didn't hear anything about nitrogen, and now suddenly it's a mortal question," farmer Micha Bouwer of the Farmers Defence Force told state broadcaster NOS.
"These are all people in the city who have two plants on their balcony and say 'nature is suffering'."
Although no concrete steps against the farmers have been announced, one political party has suggested the Netherlands reduce the number of live animals it breeds. The suggestion provoked an outcry from farming groups.
Dutch researchers on Wednesday said nitrogen emissions per capita are far higher in the Netherlands than anywhere else in the European Union.
Emissions in The Netherlands, a small, densely populated country, are four times the EU average, research institute TNO said, with 61% coming from agriculture.
(Reporting by Stephanie van den Berg, Toby Sterling and Bart Meijer; Editing by Mark Heinrich)
