After years of warnings, and a spell of hot weather that did nothing to improve the stink of tons of uncollected trash around Naples, the European Commission filed suit against Italy on Tuesday, charging that it had failed to meet its obligation to collect and dispose of its rubbish. "The piles of uncollected rubbish in the streets of Campania graphically illustrate the threat to the environment and human health that results when waste management is inadequate," Stavros Dimas, the European Union's environment commissioner, said in Brussels, referring to the southern region around Naples. "Italy needs to give priority to putting in place effective waste management plans." The suit, filed before the European Court of Justice, is aimed at pressing Italy to take more serious action against a problem that has enraged southerners, embarrassed national pride and influenced recent national elections. If the court rules against it, Italy could face substantial fines, more than a dozen years after Naples faced the first of its regular trash crises. During the campaign for an election he won last month, the prime minister-elect, Silvio Berlusconi, repeatedly promised to finally clean up the mess