Dutch farmers angered by government plans that may require them to use less fertiliser and reduce livestock began a day of protests in the Netherlands on Monday by blocking supermarket distribution hubs in several cities.
Amsterdam's Schiphol airport and KLM, the Dutch arm of Air France, have advised travellers to use public transport, rather than cars, to reach the airport, as farmers' activist groups said on social media they planned to use tractors to block roads.
Several traffic jams were reported on highways in the east of the country and on ferry routes in the north, but none near Schiphol during the morning commute.
At the heart of the protest are targets introduced last month to reduce harmful nitrogen compounds by 2030, the latest attempt to tackle a problem that has plagued the country for years.
Reductions are necessary in emissions of nitrogen oxides from farm animal manure and from the use of ammonia in fertiliser, the government says, estimating a 30% reduction in the number of livestock is needed.
High-intensity farming of cows, pigs and other animals has made the Netherlands Europe's leading emitter of the substances. Construction and traffic also contribute.
Dutch and European courts have ordered the Dutch government to address the problem. Farmers say they have been unfairly singled out and have criticised the government's approach.
Monday's protest is widely supported by farmers' groups but not centrally organised.
Previous rounds of protests have included unruly demonstrations outside the homes of politicians and lawmakers, which drew condemnation from Prime Minister Mark Rutte and did not increase public support for the cause.
In 2020 the government set a national speed limit of 100 kilometres per hour in an attempt to ease emissions.
Construction projects are now routinely delayed due to difficulties obtaining licences covering emission of nitrogen compounds.