China’s biggest economic buzzword this year could be the “six networks”, as Beijing aims to use infrastructure investment to inject fresh momentum into an economy facing persistent headwinds such as weak domestic demand and a prolonged property downturn.The scale is substantial, with investment expected to exceed 7 trillion yuan (US$1 trillion) this year alone, according to the National Development and Reform Commission (NDRC). During the five years through 2030, combined investment in just...