Photo taken on December 6, 2014 shows Tibet's Gampo Glacier.Tibet serves as an important ecological safety barrier in China, playing an important role in Asia and even in the world. Tibet's development has followed the economic law, social law and natural law. Over the past few decades, the central and regional governments, taking road of the sustainable development, have focused on the balance and unity of economy, society and ecology. At present, Tibet remains one of the cleanest regions in the world. Most of areas have maintained their original natural states. [Photo/Xinhua]

Photo taken on January 1, 2014 shows Potala Palace, the world cultural heritage, in the morning. Tibet serves as an important ecological safety barrier in China, playing an important role in Asia and even in the world. Tibet's development has followed the economic law, social law and natural law. Over the past few decades, the central and regional governments, taking road of the sustainable development, have focused on the balance and unity of economy, society and ecology. At present, Tibet remains one of the cleanest regions in the world. Most of areas have maintained their original natural states.[Photo/Xinhua]

Photo taken on July 28, 2014 shows the sheep on the pastoral area of north Tibet.Tibet serves as an important ecological safety barrier in China, playing an important role in Asia and even in the world. Tibet's development has followed the economic law, social law and natural law. Over the past few decades, the central and regional governments, taking road of the sustainable development, have focused on the balance and unity of economy, society and ecology. At present, Tibet remains one of the cleanest regions in the world. Most of areas have maintained their original natural states. [Photo/Xinhua]

Photo taken on July 26, 2014 shows that Tibetan wild donkeys are running at the Changtang Nature Reserve, southwest China's Tibet Autonomous Region. Tibet serves as an important ecological safety barrier in China, playing an important role in Asia and even in the world. Tibet's development has followed the economic law, social law and natural law. Over the past few decades, the central and regional governments, taking road of the sustainable development, have focused on the balance and unity of economy, society and ecology. At present, Tibet remains one of the cleanest regions in the world. Most of areas have maintained their original natural states. [Photo/Xinhua]

Photo taken on August 11, 2015 shows Drigung Monastery in China's Tibet Autonomous Region. Tibet serves as an important ecological safety barrier in China, playing an important role in Asia and even in the world. Tibet's development has followed the economic law, social law and natural law. Over the past few decades, the central and regional governments, taking road of the sustainable development, have focused on the balance and unity of economy, society and ecology. At present, Tibet remains one of the cleanest regions in the world. Most of areas have maintained their original natural states. [Photo/Xinhua]

Photo taken on October 19, 2013 shows Lalu Wetland that is the highest and the biggest natural wetland in the world. Tibet serves as an important ecological safety barrier in China, playing an important role in Asia and even in the world. Tibet's development has followed the economic law, social law and natural law. Over the past few decades, the central and regional governments, taking road of the sustainable development, have focused on the balance and unity of economy, society and ecology. At present, Tibet remains one of the cleanest regions in the world. Most of areas have maintained their original natural states.[Photo/Xinhua]

Photo taken on August 16, 2009 shows that black-necked cranes are dancing on the bank of Yamdrok Lake located in Nagarze County of Shannan Prefecture, southwest China's Tibet Autonomous Region. Tibet serves as an important ecological safety barrier in China, playing an important role in Asia and even in the world. Tibet's development has followed the economic law, social law and natural law. Over the past few decades, the central and regional governments, taking road of the sustainable development, have focused on the balance and unity of economy, society and ecology. At present, Tibet remains one of the cleanest regions in the world. Most of areas have maintained their original natural states.[Photo/Xinhua]

Photo taken on November 23, 2008 shows the yaks at the Changtang Nature Reserve, southwest China's Tibet Autonomous Region. Tibet serves as an important ecological safety barrier in China, playing an important role in Asia and even in the world. Tibet's development has followed the economic law, social law and natural law. Over the past few decades, the central and regional governments, taking road of the sustainable development, have focused on the balance and unity of economy, society and ecology. At present, Tibet remains one of the cleanest regions in the world. Most of areas have maintained their original natural states. [Photo/Xinhua]