"To many onlookers, a much bigger depreciation [of the renminbi] * * * seems all too plausible.
"The real worry is that China is struggling to formulate a consistent policy and to prevent a controlled decline [of the renminbi] turning into an old-fashioned run on the renminbi. * * * But it [central bank of PBOC] swiftly found itself forced to prop up the currency, spending a sixth of its foreign exchange reserves in five months. This reflects the scale of capital flight under way * * * Fitch estimates gross capital outflows from mid-2014 to the end of 2015 at more than $1tn.
Note: In quotation 2: "prevent a controlled decline [from] turning into an old-fashioned run on the renminbi"
The "from" can be omitted. See prevent (v)
(one example under definition 1.1 is: "Several neighbours rushed to help the Brownes but they were unable to prevent the men escaping")