The Aussie market gave up all of yesterday's gains amid renewed pessimism over Europe's debt crisis.
The big sell-off on Wall Street weighed heavily on sentiment, which took an added beating after Chinese economic growth slowed more than expected.
The ASX 200 tumbled 89 points (-2.1%), closing at 4187.
Resource stocks bore the heaviest punishment on the back of the Chinese data; Rio Tinto lost 5.3% whilst Fortescue sank 9.2%.
The big four were slammed alongside their international peers; NAB was the worst performing, down 2.1%.
Qantas' woes deepened after it was forced to ground more aircraft in response to striking engineers. The airliner slumped 5.2% on the day.
However Telstra was among the few bright spots (+0.6%) after its shareholders voted to approve the NBN deal.