“It is neither the sell-off in Chinese stocks nor weakness in the currency that matters most,” notes George Saravelos, a currency strategist in London with Deutsche Bank. “It is what is happening to China’s FX reserves and what this means for global liquidity. The People’s Bank of China’s actions are equivalent to an unwind of QE or, in other words, Quantitative Tightening.”
The FT story is here. Another way to put it is that a weaker Chinese currency will mean stronger currencies elsewhere and thus net deflationary pressure.