One factor in the decline is that Chinese manufacturing sector may actually be in decline. Exports to the U.S. will probably drop as U.S. growth slowed more than expected.
Samsung Electronics lost 2.9 per cent on the Seoul exchange amid speculation that its exports will shrink. In Australia the world's larges mining company BHP Billiton lost over three percent as the Australian government has passed a mining tax.
The MSCI Asia Pacific index(Hong Kong) fell 2.6 per cent to reach its lowest level since back on October 6th. Even in Asia there are worries that the European debt crisis is spreading to major economies and will curtail growth in European markets for Asian products. For much more detail see this Bloomberg article.