The mother of a schoolgirl who died of an asthma attack linked to air pollution has won the right to seek a new inquest at the high court.

The attorney general moved on Friday to quash the inquest into the death of Ella Kissi-Debrah at the age of nine, after new evidence linked it to air pollution spikes from traffic near her home in south London.

After a long fight by her mother, Rosamund Kissi-Debrah, Geoffrey Cox granted her the right to go to the high court for a new inquest.

Kissi-Debrah said: “Words cannot express how happy I am that the attorney general has taken this decision, and I would like to thank him for reaching his conclusion.

“Nothing will bring my beautiful, bright, bubbly child back, but now at least I may get answers about how she died and whether it was air pollution which snatched her away from us.

“Now I hope a new inquest will make those in power realise that our children are dying as a result of the air that they breathe. This cannot go on.

“Why is this not being taken more seriously by the government? What do we need to do to make them prioritise our children’s lives over convenience and the rights of people to pollute?”

Ella lived 25 metres (82ft) from the heavily polluted South Circular Road in Lewisham. She died in February 2013 after three years of seizures and 27 visits to hospital for asthma attacks.

An expert last year linked her death to the dangerously high levels of pollution from diesel traffic that breached legal limits.

Jocelyn Cockburn, a partner at the law firm Hodge Jones & Allen, who represents Rosamund Kissi-Debrah, said the decision was a major step towards justice for the family.

“An inquest will provide a better understanding of why she died and whether her death was avoidable. It will force the government and other bodies to account for their actions and, in many regards, their inaction on air pollution over this period,” she said.

“Air pollution is costing people’s lives and those most vulnerable are children. There is a need for more urgency into how air pollution is dealt with in urban areas to bring it within lawful limits as soon as possible.”

Kissi-Debrah believes the government’s failure to act to reduce air pollution from diesel traffic was a breach of her daughter’s human rights.

The government has repeatedly failed to bring nitrogen dioxide pollution levels to within legal limits.

Until the end of 2010, Ella had been extremely active and in good health.

But following a chest infection in October 2010, she had respiratory issues for the remainder of her short life, and was treated in five London hospitals for severe unstable asthma, with 27 separate hospital admissions over a three-year period.

An inquest into Ella’s death at Southwark coroner’s court in 2014 concluded her death was caused by acute respiratory failure and severe asthma.

Prof Stephen Holgate, an expert on asthma and air pollution, was instructed to carry out a report on her death and said there was a “striking association” between the times she was admitted to hospital and recorded spikes in nitrogen dioxide and PM10s, the most noxious pollutants, near her home.

His report said there was a “real prospect that without unlawful levels of air pollution, Ella would not have died”.

Holgate also considered the death certificate should be amended to reflect the fact that air pollution was a contributory factor in her death.

Kissi-Debrah has launched a fundraising campaign to help pay for representation at the high court hearing.

• This article was amended on 14 January 2019 because an earlier version referred to “Sir Geoffrey Cox”, however he has not been knighted. This has been corrected.