Red indicates over 200 cases of coronavirus per 100,000 head of population over the last two weeks. Dark red is used for areas with over 500 cases. The number of positive tests also plays a role in the choice of colour and this is what pushed Flanders over the edge.
In Flanders the number of cases per 100,000 head of population during the last fortnight is just under 200, but over 4% of tests are now coming back positive. In Brussels the figure is now 550 cases per 100,000.