BIG ideas often develop from roots in small places. Shanghai’s campaign to cut the city’s carbon footprint is finding success on that bottom-up path.

In the Meilong Sancun community in Xuhui District, nearly 300 residents congregate on the last Thursday of every month to exchange bags of recyclable plastic for credits toward small gifts to reward them for their efforts.

The community is one of 11 that participated in the first two-year, low-carbon trial program in residential Shanghai.