Taranto, May 15 - The president of the Taranto provincial government, Giovanni Florido, was arrested on Wednesday for alleged involvement in an environmental scandal at the troubled ILVA steel plant in southern Italy. Florido of the centre-left Democratic Party (PD) is suspected of corruption for allegedly granting favours that enabled ILVA to break environmental regulations. Three other people were also arrested on Wednesday in relation to a probe entitled 'Environment Sold Cheap'. They are former Taranto executive environmental councillor Michele Conserva, former ILVA external relations chief Girolamo Archina', and the former secretary of the province of Taranto, Vincenzo Specchia. The charges against Florido and Conserva regard authorizations for a dump. ILVA is at the centre of a long-running legal and political battle amid serious environmental and health concerns in the southern port city of Taranto, where studies suggest cancer rates are above the national average. Prosecutors from Taranto have been been fighting to close the polluting plant. But labour unions and the national government have been working just as hard to keep the plant operational while a clean-up is conducted in order to save the 20,000 jobs it provides in a region of very high unemployment. Prosecutors failed in a bid at Italy's highest court to strike down the ''Save ILVA'' decree approved late last year to keep open the troubled steel plant, Europe's largest, with many other facilities dependent on its operations.