G20 is where the worlds 20 major economies come together and talk to each other about exchange rates and refrain from a currency race to the bottom as part of a joint policy to calm financial markets and help global growth. 

http://www.scmp.com/news/china/diplomacy-defence/article/2015177/xi-jinping-closes-g20-pledge-include-emerging-markets?gclid=Cj0KEQjwpNm-BRCJ3rDNmOuKi9IBEiQAlzDJH1sSbXcW6XYVR-71rLv3UqcujS2fv99TEHenr-o-ZVQaAh2w8P8HAQ