A code yellow weather warning has been issued by the KNMI as thick fog engulfed parts of the Netherlands overnight. The warning is for parts of Drenthe, Groningen and Overijssel, under the new regional weather warning system, which was first used on Saturday. Fog consumed other areas over the weekend, including Utrecht, Noord-Brabant and parts of Gelderland and Zuid-Holland. Two freight ships collided on the Maas river near Den Bosch on Saturday morning.