THE HAGUE, Netherlands (AP) — Dutch farmers are driving their tractors in slow-moving convoys across the country to protest their treatment by the government as it seeks to rein in carbon and nitrogen emissions.

Hundreds of drivers on tractors gathered today in the central town of De Bilt to protest near the headquarters of the National Institute for Public Health and the Environment, which is responsible for measuring nitrogen emissions.

Farmers accuse the institute of inaccurately calculating nitrogen levels as the Dutch government struggles to meet European Union emissions targets in part by offering to buy up farms voluntarily.

From De Bilt, the farmers are set to drive to The Hague, where the military is helping police block roads leading to the historic town center.

The protest is the second major farmers’ demonstration this month in the Netherlands.