An Italian court has sentenced the former owners of a steelworks company to prison for more than 20 years for allowing one of its factories to emit deadly pollution for in excess of half a century. The Riva brothers, Fabio and Nicola, were handed 22 and 20 years respectively in jail for their part in letting the Ilva steel company's factory in the city of Taranto expel harmful quantities of pollutants, wrapping up a trial that has lasted for five years.