COPENHAGEN (REUTERS) - From penalising cars to planting trees, dozens of mayors from every continent pledged cleaner air on Friday (Oct 11) in a bid to improve urban health and tackle climate change.
More than 90 per cent of people breathe dirty air, causing death and disease, according to the World Health Organisation (WHO).
"This dirty air kills seven million people a year, largely in cities, and contributes to the global climate emergency," United Nations Secretary-General Antonio Guterres told the C40 summit of world mayors in Copenhagen.
Leaders of more than 90 cities representing more than 700 million people and a quarter of the global economy met in the Danish capital this week to push climate action.
As activists from Swedish teenager Greta Thunberg to the "Extinction Rebellion" protest movement take an increasingly visible stand on climate change, officialdom is catching up.
Among the mayoral initiatives are incentives to "do good" - cheap bus fares - and penalties for doing harm - such as spewing excess emissions - as cities test tactics to coax change.
From Los Angeles to Tokyo, 34 cities committed on Friday to meet WHO minimum air quality levels by 2030 - something they said could save 40,000 lives a year - and report on progress.
"Air pollution is a global crisis, and as mayors, it is our fundamental responsibility to protect our citizens from the dangerous health implications associated with breathing dirty air," said Mayor of London Sadiq Khan.
The mayors met in the Danish capital - a Viking village turned city of wind turbines - days after climate-change protesters took to the streets from Austria to New Zealand pledging two weeks of peaceful civil disobedience.
Delegates at the summit opening were met on Wednesday by demonstrators from local group Klima Aktion DK, armed with fake binoculars made from toilet rolls.
"Our message to the C40 Mayors is: The people are watching you! We want to see action!" the group wrote on Facebook.
LONDON TO LISBON
More than two million people live in areas of London that have illegally high levels of air toxins, according to official data.
To change that, the city this year introduced the world's first Ultra Low Emission Zone, requiring all vehicles to meet strict standards or pay a fee to enter the centre, Mr Khan said.
Others offered carrots instead of sticks.
The mayor of Lisbon, Mr Fernando Medina, said the Portuguese capital launched a discounted single fare ticket in April that had already resulted in a 30 per cent increase in public transport use.
It has also increased green spaces, he said, with the equivalent of some 200 football pitches newly planted.
Milan's Mayor Giuseppe Sala said the Italian city was implementing a large low-emission zone and planned to completely switch its bus fleet to electric within seven years.
"Politically it is not easy to tell people they can't use their car but at this moment it is necessary," Mr Sala told the Thomson Reuters Foundation on the sidelines of the conference.
Cities are vital to limiting global warming, as they account for about three-quarters of carbon emissions and consume more than two-thirds of global energy, according to the United Nations.
Known technologies such as electric buses could deliver more than half the cuts needed to keep global temperature rises below 2 deg C, the UN says.
"Bold and ambitious climate action has the added benefit of reducing harmful pollution and cleaning the air we breathe,"said the mayor of Los Angeles, Mr Eric Garcetti.