China and the United States are the world's two biggest carbon dioxide emitters, but what approach are these countries' governments taking in the fight against climate change?

In Shenzhen, one of China's most populous cities, new regulations to tackle air pollution are helping to unleash a revolution in clean energy and transport. Stephanie Wong visits Shenzhen to learn more about how the city is cleaning up its transport. 

Meanwhile, the tone has changed in Washington, DC, with the Trump administration rolling back much of the environmental policies that had been made over the past decade. Russell Beard attends the march and speaks to some of the men and women at the forefront of a global network of grassroots resistance.