If China is the globe’s most powerful manufacturing engine, the port of Shanghai is its fuel injection valve. This harbor is the world’s busiest, both in terms of tonnage and number of containers processed, allowing China to import the raw materials fueling its development and export the products that represent a significant share of the world’s economy.

China’s “strictest air protection law” yet took effect on January 1, 2016, promising to bring big changes to its smog-filled cities. But some municipal governments have been ahead of the curve, working to clean up the air through experimentation and innovation. Shenzhen, China’s first special economic zone and which recently passed its neighbor Hong Kong to lead China’s most competitive cities, is one of these.

There’s perhaps no better evidence of China’s growing appetite for American agricultural products than the ongoing transformation of the port of Oakland.

Shenzhen sits in subtropical south China, where four-fifths of the country’s water resources flow. The monsoon brings heavy rains from April to September; at its peak, Shenzhen’s more than 7 million residents see pouring rain almost every day. So why is this city facing a serious water shortage?

Although treating wastewater generally ranks alongside police and fire safety, schools, and transit as the top priorities of any sensible city hall, new ideas about cleaning up sewage almost never attract headlines or TV airtime. In its 90-year history, for instance, The New Yorker, the most urbane and expansive magazine in the country, has never published a feature article on sewage treatment.

In March 1999, not long after he was sworn in as the 47^th mayor of Oakland, Jerry Brown called Lesley Estes, the supervisor of the city’s watershed protection program. Brown, who is now California’s governor, wanted the city staffer he called “Creek Lady” to describe the most formidable ideas she had to conserve natural areas, make parks more beautiful, and clean up the city’s waters.