Quick fact about China's Pearl River Delta. It is considered the world's largest megacity today and it already has more people than Australia (23 mi), Canada (35 mi) or Argentina (41 mi).
If you want some academic publications on China's Pearl River Delta region, you can fin some interesting studies conducted by researchers from the Seto Lab on Urbanization and Global Change (Yale). I got this Time-Lapse from their website and it gives a glimpse of the fast urbanization process of this region over the past decades.