China & the emerging economies are watched like hawks by the investment community as they are a (current) barometer for forward demand of commodities, energy & manufacturing output.
If there are any fears whatsoever that the far east is likely to struggle or miss their key economic numbers it has a knee jerk effect on Australian, New Zealand & Canadian markets & consumers. Add to that the knock-on effects of soft data coming out of the US & slow European manufacturing & construction industry output & you begin to experience a gradual escalation of mild panic in investor sentiment over fears of an uptick in global slowdown/recessionary concerns.
The results will manifest themselves in exhaustive/consolidatory behavior & spikey, over-extended price dumps & you will hear a lot more emphasis directed towards risk on-risk off or flight to safety comments in analyst & newswire rhetoric.
As has been advised on here many times, it pays to stay abreast of generic fundamental sentiment as that is what directly influences & orchestrates price action, both in the short & medium term.