Turmoil has returned to Chinese financial markets after more than two years of relative calm, reviving memories of 2015-16, when an equity market rout combined with currency depreciation captured the attention of global investors and sparked worries about systemic risk.

Market declines this year have not yet reached the magnitude of 2015, when the Shanghai Composite index fell by more than 45 per cent in just over two months between June and August, while the renminbi depreciated by 10 per cent between August 2015 and the end of 2016.

The moves prompted heavy-handed intervention in both markets. While the use of foreign exchange reserves to support the renminbi is generally viewed as a successful — if costly — effort to stabilise market expectations, the stock market bailout is widely seen as a failure.