Every year, half a million babies under one-year-old die due to polluted air, according to data from the State of Global Air 2020 report.

Every day, the World Health Organisation warns that 93% of the world's children under the age of 15 years breathe air that puts their health and development at serious risk.

A uterus doesn't provide a total barrier against pollution, with fine particulate matter, known as PM2.5, being found in the placenta, as well as toxic air increasing the risk of low birth weight and stillbirths.

From before birth, air polluted by NO2 ( nitrogen dioxide) and PM2.5 - mainly originating from vehicle traffic and industry - damages health and continues to do so throughout one's life.

Rosamund Kissi-Debrah lives beside London's South Circular Road, one of the UK capital's most traffic-heavy roads. Her daughter, Ella, was the first person in the UKto have air pollution listed as a cause of death on their death certificate.

Rosamund describes Ella as a sporty and happy little girl, living life to the full despite suffering from severe asthma.

But at the age of six, her condition rapidly deteriorated, with her mother having to carry her around as she couldn't walk due to her respiratory failure.

On February 15, 2013, Ella, aged nine, died after a severe asthma attack and cardiac arrest.

An inquest into her death found that air pollution was a significant contributor to both the induction and exacerbations of her asthma.