When driving in heavy rain, is it compulsory to use any lighting?

Dipped headlights must be used together with sidelights at any time of day, on both urban and interurban roads, under meteorological or environmental conditions that significantly reduce visibility, such as fog, heavy rain, snowfall, clouds of smoke or dust, or any other similar circumstance. In these cases, the dipped headlights may be used alone or simultaneously with the front fog light.