Rome, August 1 - A decree to save Europe's biggest steel plant ILVA while working to make sure it stops polluting the Puglia city of Taranto passed in the Senate on Thursday. The decree, among other things, designates a group of experts to oversee clean-up of the Taranto steel plant. ILVA has been at the centre of a political and legal battle since July 2012 when local magistrates ordered the partial closure of the Taranto plant due to serious health concerns. The Riva group, which owns the ILVA steel plant, is the biggest iron and steel producer in Italy, the fourth-biggest in Europe and the 23rd-biggest in the world. Earlier this month, prosecutors asked the courts to indict Emilio Riva, ILVA's former head, on charges of massive tax fraud. Milan prosecutor Francesco Greco accused Riva, and two other former executives of the steelmaker, of evading 52 million euros in taxes dating back to 2007.