London mayor Sadiq Khan announces car-free day to tackle pollution crisis

London (CNN)London is to get a much-needed breath of fresh air on its most extensive car-free day to date, with 12.4 miles (20km) of road to be closed in the centre of the British capital. Vehicles are responsible for around half of harmful nitrogen oxide air emissions in the British capital, the mayor’s office said in April. They contribute to a toxic air health crisis that increases the risk of asthma, cancer and dementia as well as causing thousands of …