Volkswagen supervisory board to discuss cartel issue: source

BERLIN (Reuters) - Volkswagen will hold an extraordinary supervisory board meeting to discuss allegations about a cartel in the auto industry, a source familiar with the matter said on Monday.

A VW spokesman confirmed that an extraordinary supervisory board meeting would be held on Wednesday but declined to give further details.

German magazine Der Spiegel said German carmakers Daimler, VW, BMW and Porsche held discussions about how to calibrate the size of tanks containing AdBlue, a urea-based liquid needed to help filter nitrogen oxides from diesel emissions.

(Reporting by Andreas Cremer; Writing by Edward Taylor; Editing by Maria Sheahan)