WHO chief: Air pollution link to 600,000 deaths in children
The director general of the World Health Organization has said air pollution is "one of the most pernicious threats" facing global public health today and is on a much bigger scale than HIV or Ebola.
Dr Margaret Chan told the Today programme that poor air quality was having a disproportionate impact on the young.
She said indoor and outdoor pollution was linked to the deaths of hundreds of thousands of children each year.
A week of coverage by BBC News looking at ways to cut air pollution.