Rich-world problem of low inflation has arrived in emerging markets

For years, low inflation looked like a classic rich-world problem. Plenty of developing economies now have some version of it too.
 
Central banks have responded like their developed-country peers: by lowering interest rates. They have more room to keep going -- but they also face more obstacles on the way down.
 
The biggest ones are their currencies, which don’t loom so large for rich-world central bankers (although US President Donald Trump thinks they should).
 
Emerging-market exchange rates get bounced around as capital shifts in and out -– flows that have been amplified by years of cheap money