Momentum continues to grow for new bus technologies among C40 cities. With the recent addition of Changwon, Hong Kong and Los Angeles, 26 cities have now signed on to the C40 Clean Bus Declaration, demonstrating the market potential for these new technologies to manufacturers. Signatory cities will have over 175,000 buses in their fleet by 2020, and have committed to switching over 45,000 of these to low emission. If the clean bus goals of these 26 cities are reached, GHG savings would be almost 1.3mn tonnes per year – if the cities manage to switch their entire bus fleet to low emission, the savings could be 2.8mn tonnes each year.

The Declaration was recently showcased in various discussions around city climate action at COP 21 in Paris. Transport is a massive opportunity area for reducing emissions; bus fleets in particular are owned/controlled by cities and are a great example of where cities can make a difference.

Many signatory cities have made ambitious commitments; for example, 20% of London’s bus fleet will shift by 2016 and 40% by 2020 to a combination of hybrid, full electric and hydrogen fuel-cell buses. In addition, we know that the Declaration is working and the market is responding as a result of demonstrating this global demand, as London has already been able to secure a 10% reduction in the price of hybrid buses.

However more needs to happen. Mayor of London Boris Johnson emphasised this point: “In London, hybrid, electric and hydrogen buses have helped transform our bus fleet. Now with 26 cities supporting our C40 Clean Bus Declaration we need more businesses to get on board to lower manufacturing costs and help reduce global emissions.”

The Declaration and its 20 original signatories were first announced at the C40 Latin American Mayors Forum in Buenos Aires in March 2015. It was championed by London –lead city of the C40 Low Emission Vehicle (LEV) Network – and is a key outcome of a meeting between LEV Network cities in November 2014 in Bogotá.

The Declaration is intended to give cities a strong foundation for conversations with bus manufacturers and funding agencies to tackle the issue of high capital premiums on new bus technologies. It brings together mayoral support behind the critical issue of moving to clean buses in cities, and sends a strong statement about the interest of mayors in seeing action on this front across the world. The Declaration also brings together, for the first time, the global scale of demand for clean buses across the C40 network by documenting clean bus targets, and the anticipated number of buses to be purchased over the coming years. 

The C40 Clean Bus Declaration is still open to all C40 mayors to sign on. Cities wishing to sign up to the Declaration should reach out to Gunjan Parik ( or Kat Urquhart ( 

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