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.
Sign up for our daily newsletter
Sign up for The Top of the World, delivered to your inbox every weekday morning.