A convention is held to celebrate the 60th anniversary of the campaign of democratic reform in Tibet in the Potala Palace square in Lhasa, capital of southwest China`s Tibet Autonomous Region, March 28, 2019. (Xinhua/Li Xin)

A convention is held to celebrate the 60th anniversary of the campaign of democratic reform in Tibet in the Potala Palace square in Lhasa, capital of southwest China`s Tibet Autonomous Region, in this aerial photo taken on March 28, 2019. (Xinhua/Purbu Zhaxi)

A convention is held to celebrate the 60th anniversary of the campaign of democratic reform in Tibet in the Potala Palace square in Lhasa, capital of southwest China`s Tibet Autonomous Region, March 28, 2019. (Xinhua/Purbu Zhaxi)

A convention is held to celebrate the 60th anniversary of the campaign of democratic reform in Tibet in the Potala Palace square in Lhasa, capital of southwest China`s Tibet Autonomous Region, March 28, 2019. (Xinhua/Li Xin)

A convention is held to celebrate the 60th anniversary of the campaign of democratic reform in Tibet in the Potala Palace square in Lhasa, capital of southwest China`s Tibet Autonomous Region, March 28, 2019. (Xinhua/Li Xin)