Fig. 1: Correlation between economic growth and water use in the BTH region and existing world-class megalopolises (year 2017).
From: Water scarcity will constrain the formation of a world-class megalopolis in North China

A plot of GDP versus annual per capita water use in the BTH region and the six existing world-class megalopolises. It demonstrates a high correlation between the economic growth of the world-class megalopolises and the abundance of water resources.