In its yearly awards ceremony, C40 Cities singled out megacities around the world which are leading the way in terms of combating climate change, often with innovative initiatives.
Climate action plans and inventories The city's Climate Action Plan 2015 ultimately won it this category. Portland is currently on target to reduce its greenhouse gas emissions by 40% by 2030, and 80% by 2050. Currently, half of its citizens use public transport, walk, or cycle rather than using a car.
Adaptation plans and assessments Paris's climate adaptation strategy was honoured this year, with the city working on a plan to reduce the effects of urban heatwaves, flooding and droughts by 2020.
Melbourne and Sydney, Australia
Building energy efficiency These Australian cities have both put a programme known as CitySwitch Green Office into action, looking to reduce the gap between owners and tenants by encouraging them to work together to lower CO2 emissions from their building.
Clean energy Yokohama's Smart City Project hopes to reduce CO2 emissions by 80% by 2050. City officials are working to engage both inhabitants and stakeholders to meet their target.
Finance and economic development Despite being one of the fastest growing cities in the world, Shenzhen has committed to implementing an Emissions Trading System (ETS). The scheme has so far recruited 636 companies to participate in green, low carbon development of the city.