	Land			Buildings			Building improvement			Machinery and equipment			Motor vehicle and other asset			Office equipment			Construction in progress			Total
	US$’000			US$’000			US$’000			US$’000			US$’000			US$’000			US$’000			US$’000
Cost
At January 1, 2020		6,838			50,543			7,030			103,869			6,009			7,092			1,378			182,759
Additions	—				—			138			239			265			363			15,691			16,696
Disposals	—				—			(31	)		(6,129	)		(483	)		(205	)	—				(6,848	)
Transfer	—				680			152			1,157			115			17			(2,093	)		28
Exchange differences		34			893			47			1,129			63			321			685			3,172
At December 31, 2020		6,872			52,116			7,336			100,265			5,969			7,588			15,661			195,807
Additions		—			—			6			406			374			761			7,109			8,656
Disposals		—			(37	)		—			(7,232	)		(517	)		(474	)		—			(8,260	)
Transfer		—			(45	)		108			4,523			88			11			(4,642	)		43
Exchange differences		(856	)		(3,942	)		(613	)		(9,798	)		(438	)		(339	)		(1,316	)		(17,302	)
At December 31, 2021		6,016			48,092			6,837			88,164			5,476			7,547			16,812			178,944

Depreciation/Impairment
At January 1, 2020		—			(36,870	)		(4,464	)		(90,132	)		(3,662	)		(5,884	)		—			(141,012	)
Depreciation charge for the year		—			(962	)		(384	)		(2,301	)		(514	)		(414	)		—			(4,575	)
Impairment		—			—		—				(198	)	—				(4	)		—			(202	)
Disposals		—			—			21			6,128			438			203			—			6,790
Transfer		—			—			—			—			(56	)		—			—			(56	)
Exchange differences		—			(653	)		(29	)		(1,041	)		(63	)		(266	)		—			(2,052	)
At December 31, 2020		—			(38,485	)		(4,856	)		(87,544	)		(3,857	)		(6,365	)		—			(141,107	)
Depreciation charge for the year		—			(993	)		(403	)		(2,184	)		(504	)		(506	)		—			(4,590	)
Impairment		—			—			—			(5	)		—			(2	)		—			(7	)
Disposals		—			36			—			7,170			505			468			—			8,179
Transfer		—			45			—			—			(87	)		—			—			(42	)
Exchange differences		—			3,389			428			8,639			268			318			—			13,042
At December 31, 2021		—			(36,008	)		(4,831	)		(73,924	)		(3,675	)		(6,087	)		—			(124,525	)

Net book value
At December 31, 2021		6,016			12,084			2,006			14,240			1,801			1,460			16,812			54,419
At December 31, 2020		6,872			13,631			2,480			12,721			2,112			1,223			15,661			54,700
At January 1, 2020		6,838			13,673			2,566			13,737			2,347			1,208			1,378			41,747

In 2021, 2020 and 2019 our Company recorded an impairment loss of $7, $202 and $546 on property, plant and equipment at Sigma Cable, Shanghai Yayang and SFO facilities. The impairment is presented within cost of sales in consolidated income statements, other operating expenses in Note 7(b), and the impairment of property, plant and equipment of ROW, North Asia and Thailand segments in Note 5.

Our Company identified impairment at Sigma Cable due to lack of profitability. Our Company determined that certain machinery and equipment would not generate the expected future cash flows. The impairment test revealed that the total carrying amount of these assets was greater than their total recoverable amount. After considering the relevant objective evidence, our Company recorded an impairment loss.

Our Company performed a valuation for utilized machinery measured at fair value less costs to sell using a cost approach due to closure of the manufacturing facilities at Shanghai Yayang. Its fair value measurement was classified as Level 3 of the fair value hierarchy. After considering the relevant evidence, the key assumption used included replacement costs, residual value and remaining useful life of these existing assets. The impairment test revealed that the recoverable amount was lower than the carrying amount.

Our Company considers the market demand for SFO’s products and performed an impairment test on the CGU composed of property, plant and equipment used in the manufacturing of fiber optic cables at SFO. Our Company determined the recoverable amount of the CGU to be $0 based on the value in use.

Information about the property, plant and equipment that were pledged to others as collaterals is provided in Note 27(e) (i).