Electric vehicles took centre stage at this year's Geneva Motor Show, as automakers scrambled to bring their fleets into line with strict CO2 emissions standards set to kick in next year.
Some 385,000 people worldwide died prematurely in 2015 from air pollution caused by vehicle exhaust emissions, a US study has found, singling out diesel engines as the main culprit.
Which European cities have the worst air quality? This interactive graphic shows where the concentration of nitrogen dioxide is the highest.
After more than 150 years, Germany's last black coal mine will close in the Ruhr region, posing a gigantic geological and environmental challenge to the former industrial heartland.
Industry wants to curb nitrogen oxide emissions from diesel engines using modern catalytic converter technology. One possibility is the admixture of AdBlue, which contains urea. But how exactly does it work?