summarize What has China done? China's central bank has devalued the yuan by nearly 2% against the US dollar for the second time in two days to boost exports and take it a step nearer to becoming an official reserve currency. Why has Beijing acted now? Industrial production, investment and retail sales data for July were weaker than expected, while at the weekend figures showed Chinese exports tumbled 8.3% in July, their biggest drop in four months. After a string of weakening output growth figures going back to last year, the authorities have come intense pressure internally to address the slowdown with a dramatic policy shift. Why focus on the currency's value? The dollar has appreciated over the past year in anticipation of the US raising interest rates for the first time since the financial crisis. Since the yuan loosely tracks the dollar, it has been dragged higher - keeping its differential with the greenback roughly the same, but at the expense of making the country's goods dearer compared to regional rivals, especially South Korea and Japan. That has hit Chinese exports badly. Now the US Federal Reserve is close to its first rate rise in seven years, potentially pushing