Exposure to indoor and outdoor air pollution is almost as dangerous as smoking, reducing life expectancy by an average of 20 months, according to a major study.

The report, the State of Global Air, is the latest in a slew of evidence on the links between air pollution and poor health.

It shows that breathing toxic air – both inside and outside the home – will cut the life expectancy of a baby born today by an average of 20 months, compared to a 21-month fall in life expectancy in a smoker.

Worldwide, air pollution contributed to nearly five million deaths from stroke, heart attack, diabetes, lung cancer and chronic lung disease in 2017.

Children born in the most polluted countries of the world – Bangladesh, India, Nepal and Pakistan – face the greatest threat from air pollution. Babies born here face lost life of around two years and six months, the report found.