Exhaust fumes from diesel engines do cause cancer, according to a panel of experts working for the World Health Organization. It concluded that the exhausts were definitely a cause of lung cancer and may also cause tumors in the bladder. It based the findings on research in high-risk workers such as miners, railway workers and truck drivers. Diesel was previously listed as a "probable" carcinogen. The World's science editor David Baron talks with anchor Lisa Mullins about regions in the world where people are most affected by diesel fumes.