A disturbing UN report on the risks we face if global warming exceeds 1.5°C has focused attention on the drastic environmental action needed to avoid the worst, with the transport sector among those singled out for urgent measures.
The transport sector is the fastest growing contributor to climate emissions and particles from cars and other vehicles - including black carbon and nitrogen dioxide - also contribute to a range of illnesses including respiratory conditions, strokes, heart attacks, dementia and diabetes.
Across the world, governments and city authorities are introducing cleaner public transport and pledging to ban the most polluting vehicles in a bid to reduce the harmful impact of a sector that is only set to grow.
Innovation, legislation and public awareness are key to ensuring that sustainable transport becomes a reality before it is too late. Already, the message is getting through.
In September, a British transport company, Go-Ahead Group, introduced a bus fitted with a specially designed filter that removes ultrafine particles from the air and traps them as the bus moves along. The filter allows the bus to blow out pure air so that the air behind is cleaner than the air in front.
Air pollution causes an estimated 40,000 early deaths in the United Kingdom every year. The British government, which has lost three court cases over air quality since 2015, plans to ban new petrol and diesel cars and vans from 2040 as part of a 3 billion pounds (US$3.9 billion) clean air strategy. Campaigners say this needs to happen earlier to tackle what ministers have called a "public health emergency".
France has also pledged to end the sale of petrol and diesel vehicles by 2040 while Denmark has proposed a full ban on new petrol and diesel cars by 2030 and on hybrid vehicles from 2035. The mayors of Paris, Madrid, Mexico City and Athens have said they plan to ban the most polluting diesel vehicles from city centres by 2025.
UN Environment has made air pollution a priority, urging governments and local authorities to join the Breathe Life campaign it runs with the World Health Organization and the Climate and Clean Air Coalition. The campaign, which supports cleaner air initiatives and promotes the use of clean energy, reaches over 97 million people worldwide.
As well as motivating authorities to take action, the campaign raises awareness of what individuals can do to be part of the solution by, for example, reducing consumption of meat and dairy, composting food and garden waste, using public transportation, or switching to a hybrid or electric vehicle.
There are now more than a million electric cars in Europe, with sales up more than 40 per cent in the first half of this year. Norway, which has a comprehensive set of fiscal and non-fiscal measures to support the sale of electric vehicles, has the most, followed by Germany.
The European Parliament has approved a draft law to reduce emissions of carbon dioxide from new cars by 20 per cent by 2025 and 40 per cent by 2030. Ministers also set a target for 30 per cent of all new car and van sales to be electric by 2030.
The UN report from the Intergovernmental Panel on Climate Change noted that electrification is a powerful measure to "decarbonize" passenger cars, two and three wheelers, and the rail sector.
"In road freight transport (trucks), systemic improvements (in supply chains, logistics and routing) would be effective measures with efficiency improvement of vehicles. Shipping and aviation are more challenging to decarbonize while their demand growth is projected to be higher than other transport modes. Both modes would need to pursue highly ambitious efficiency improvements and use of low-carbon fuels," it said.
UN Environment's electric mobility programme works with countries, especially emerging economies, to support a shift from fossil fuels to electric vehicles by exchanging best practices and supporting the development of strategies and roadmaps at national and regional level.
Electrification of public transport is on the rise with China leading the way in battery-electric buses. Last year, the southeastern city of Shenzhen said all of its more than 16,000 buses had gone electric, giving it the world's first 100 per cent electrified bus fleet.
In Germany, Siemens worked with bus operators to provide re-charging stations for models from different manufacturers, a key step in ensuring interoperability.
In Adelaide, Australia, city authorities introduced the world's first electric solar-powered bus in 2013 while London plans to add 68 new zero-emission double-decker buses to its fleet next year, bringing the total number of electric buses in the city to 240. By 2037, all buses in London will be zero-emission, authorities say.
These kinds of pioneering solutions to environmental challenges will be at the heart of the fourth UN Environment Assembly to be held in March next year. The theme is innovative solutions for environmental challenges and sustainable consumption and production.
The simple truth is that we are consuming and producing too much, and our planet cannot bear the strain--that message rang loud and clear from the IPCC report. The Environment Assembly's motto is to Think Beyond and Live Within: to think beyond prevailing patterns and live within sustainable limits to tackle environmental challenges and assure a prosperous future.
Ahead of the United Nations Environment Assembly next March, UN Environment is urging people to Think Beyond and Live Within. Join the debate on social media using #SolveDifferent to share your stories and see what others are doing to ensure a sustainable future for our planet.