Workers build a modular house in Shijiazhuang, capital of north China's Hebei Province, June 20, 2015. A local company showed their modular house made by recycled materials. The modularization design brings no pollution during building process and could save two thirds of the construction time. (Xinhua/Li Mingfang)

People visit a modular house in Shijiazhuang, capital of north China's Hebei Province, June 20, 2015. A local company showed their modular house made by recycled materials. The modularization design brings no pollution during building process and could save two thirds of the construction time. (Xinhua/Li Mingfang)

Workers build a modular house in Shijiazhuang, capital of north China's Hebei Province, June 20, 2015. A local company showed their modular house made by recycled materials. The modularization design brings no pollution during building process and could save two thirds of the construction time. (Xinhua/Li Mingfang)

Workers build a modular house in Shijiazhuang, capital of north China's Hebei Province, June 20, 2015. A local company showed their modular house made by recycled materials. The modularization design brings no pollution during building process and could save two thirds of the construction time. (Xinhua/Li Mingfang)

Workers build a modular house in Shijiazhuang, capital of north China's Hebei Province, June 20, 2015. A local company showed their modular house made by recycled materials. The modularization design brings no pollution during building process and could save two thirds of the construction time. (Xinhua/Li Mingfang)

Workers build a modular house in Shijiazhuang, capital of north China's Hebei Province, June 20, 2015. A local company showed their modular house made by recycled materials. The modularization design brings no pollution during building process and could save two thirds of the construction time. (Xinhua/Li Mingfang)

People visit a modular house in Shijiazhuang, capital of north China's Hebei Province, June 20, 2015. A local company showed their modular house made by recycled materials. The modularization design brings no pollution during building process and could save two thirds of the construction time. (Xinhua/Li Mingfang)

Workers build a modular house in Shijiazhuang, capital of north China's Hebei Province, June 20, 2015. A local company showed their modular house made by recycled materials. The modularization design brings no pollution during building process and could save two thirds of the construction time. (Xinhua/Li Mingfang)

People visit a modular house in Shijiazhuang, capital of north China's Hebei Province, June 20, 2015. A local company showed their modular house made by recycled materials. The modularization design brings no pollution during building process and could save two thirds of the construction time. (Xinhua/Li Mingfang)

Workers build a modular house in Shijiazhuang, capital of north China's Hebei Province, June 20, 2015. A local company showed their modular house made by recycled materials. The modularization design brings no pollution during building process and could save two thirds of the construction time. (Xinhua/Li Mingfang)