About time. Driving up to Guangzhou a couple of weeks ago the haze of smog was shocking, and the reduced air quality was immediately apparent.

Rapid industrialization and a burgeoning middle class have strained resources in China, with devastating effects on its air, land, and waterways. Coal-burning plants have fueled regular smog crises in some parts of the country, and widespread pollution has put extra pressure on limited water supplies. Earlier this month, the government announced that one-fifth of its farmland is contaminated by pollutants like cadmium and arsenic. And despite world-leading investments in renewable energy, China continues to rely heavily on fossil fuels to meet its energy needs: it remains the world's largest emitter of carbon dioxide, and accounts for about one-third of the world's greenhouse gas emissions.