In 2018, China rolled out its "river chief" scheme to tackle water pollution. By mid-2018, 31 provinces, autonomous regions, and municipalities across the country fully established the scheme, appointing more than 300,000 river chiefs in a four-tier system from provincial to township levels. In addition, the 29 provinces have also appointed 760,000 river chiefs at the village level. 

So, what is a river chief?