Technology helps to clean up a dirty business

Mobile apps are making garbage collection more efficient and eco-friendly. Hou Liqiang reports.

Editor's note: In the wake of new regulations to encourage trash sorting across Shanghai, this is the first of two stories focusing on the central government's efforts to introduce the practice in Beijing, before expanding it to other cities around the country.

Lin Ming used to spend most of his working day riding a tricycle through Beijing's streets and alleys, bellowing "waste collection" at intervals. He described himself as a "guerrilla", who often played cat-and-mouse with urban patrol officers known as chengguan.