BASF has to curtail production because it can no longer sufficiently cool some plants at its Ludwigshafen headquarters with water from the river Rhine. That is due to low water levels and regulatory limits to how much the river water can be warmed up further by industry, it said in a statement on Friday.

"In individual cases there could be supply constraints if the current weather conditions prevail. BASF is in close contact with its customers," it said.

Low water levels in the Rhine could also lead to reduced shipments via river vessels, though BASF can work around that for now, it added.

(Reporting by Ludwig Burger; Editing by Maria Sheahan)