The Shanghai Composite suffered its largest one-day percentage fall of the 2015 crash on August 24, 2015.
The index fell 8.49% that day, a session widely known in financial reporting as Black Monday. The decline came after months of turbulence following a rapid rise in Chinese mainland share prices and a major sell-off that began in June.
Investors were concerned about slowing Chinese economic growth, falling commodity prices, weak industrial data, and uncertainty surrounding government market interventions. Sharp falls in other global markets showed how closely international investors had become connected.
The date is sometimes confused with July 27, another severe session during the same episode. The wider turbulence continued into early 2016, so August 24 identifies the biggest one-day fall rather than the complete start or end of the market downturn.