The mother of a London girl who died from air pollution exposure has called for a new international law that forces governments to clean up the environment for future generations. Rosamund Kissi-Debrah’s remarks come as a coroner made legal history on Wednesday by ruling that illegal levels of pollution, predominantly caused by traffic emissions, caused her daughter Ella’s death. Philip Barlow, the inner south London coroner, said the nine-year-old was exposed to nitrogen dioxide and particulate matter pollution in excess of European Union and World Health Organisation standards. It is believed the ruling is the first in the world to identify air pollution as a cause of death. Ms Kissi-Debrah said after the ruling: “We’ve got the justice for her which she so deserved. “I think that it would be a fitting legacy, to bring in a new Clean Air Act and for governments – I’m not just talking about the UK government, but governments around the world – to take this matter seriously. “My biggest desire is to prevent future deaths, anything that saves future lives I am going to be in support of.” The ruling concludes a years-long campaign by Ms Kissi-Debrah to have her daughter’s death examined by a second coroner. Ella lived within 25 metres of the South Circular Road in Lewisham, a busy London arterial road, and other high-traffic routes. The coroner ruled that high nitrogen dioxide levels exacerbated her severe asthma. He said the "recognised failure" of governments to bring pollution down to safe levels had probably contributed to her death. “The whole of Ella’s life was lived in close proximity to highly polluting roads,” Mr Barlow said. “I have no difficulty in concluding that her personal exposure to nitrogen dioxide and PM was very high.” Prof Stephen Holgate, a respiratory expert from the University of Southampton, testified at the inquest that the toxic air Ella was exposed to at her home caused her final acute asthma attack in 2013. He said the nine-year-old was a “canary in the coal mine”, signalling the risk to other Londoners.