Australian shares slumped for a fifth straight session - and are once again testing 5000 levels - as China's currency devaluations continue to frighten global investors.
China was forced to again suspend sharemarket trading following a 7 per cent slide in its market, ahead of the release of new rules which are aimed at restoring investor confidence.
The benchmark S&P/ASX200 sank 2.2 per cent on Thursday to 5010.3, while the broader All Ordinaries fell 2.1 per cent to 5068.8. 
The ASX suffered its worst one-day performance in more than three months, its worst week since   August 2011, and its worst start of the year on record, chalking up a loss of 5.4 per cent, or $78 billion in market capitalisation, in 2016.
Overseas leads were poor, with a 1.5 per cent drop in the Dow Jones and Brent crude oil falling to 2004 levels, ahead of the renewed slump in China which triggered heavy selling on key markets in the region and on the local bourse.
Domestic economic data didn't help, with building approvals dropping 12.7 per cent in   November after a 3.3 per cent rise in the previous month. The fall far exceeded expectations of a 3 per cent drop and is a worry as the housing construction boom is seen as one of the few bright spots in the economy.
But the losses accelerated when, about midday, the People's Bank of China set the yuan's official midpoint rate 0.51 per cent lower at 6.5646 per US dollar. That was the biggest daily fall since last   August, when Beijing surprised the market with an abrupt near 2 per cent devaluation of the Chinese currency.
The news spooked investors, with Chinese stock exchanges suspended for the second time this week after the CSI 300 Index plunged more than 7 per cent.
"There was a few data releases for Australia - building approvals, which missed, and we also had trade numbers, which were slightly weak as well," Russell Investments portfolio analyst Andrew Zenonos said. "But the key thing has been the Chinese decision to weaken the currency further.
"Once that came out the Chinese market opened quite lower and put further pressure on the Australian market." Commodity and banking stocks had been hard hit, he said.
"Overnight we saw energy and commodities selling off quite heavily so we've seen a big move down in BHP. In the energy space we've seen stocks like Santos and Oil Search being hit quite hard as well. After we saw the weak economic data come out of Australia we also saw the banks being sold off," Mr Zenonos said.
In a sign of just how worried financial markets are about the developments in China, the oil price also fell sharply after Beijing devalued the yuan. The price for benchmark Brent fell as much as 3.3 per cent in Asian trade to $US33.09, the lowest in more than 11 years, extending a hefty 6 per cent overnight slump.
Other regional markets were reeling too, with Japan's Nikkei down 2.2 per cent in late trade, the Hang Seng in Hong kong losing 2.4 per cent and the Singapore Straits index falling 2.2 per cent.
BHP was crunched 4.8 per cent to $16.33 while Rio Tinto also shed 4.8 per cent to $40.70.
Telstra fell a more modest 1.5 per cent to $5.32. The banks all fell: ANZ by 3.2 per cent to $25.86, Commonwealth Bank 2.1 per cent to $80.41, NAB 3.3 per cent to $28.02 and Westpac 2.9 per cent to $31.28.
Energy stocks were also dumped with Santos down 7.4 per cent to $3.25 and Woodside 5.1 per cent to $26.94.