A medical expert carries out CHD screening for students in Qushui County of Lhasa, capital of southwest China`s Tibet Autonomous Region, April 22, 2022. (Xinhua/Zhang Rufeng)

A medical expert carries out CHD screening for a student in Qushui County of Lhasa, capital of southwest China`s Tibet Autonomous Region, April 22, 2022. (Xinhua/Li Jian)

A medical expert registers a student for CHD screening in Qushui County of Lhasa, capital of southwest China`s Tibet Autonomous Region, April 22, 2022. (Xinhua/Zhang Rufeng)

A medical expert carries out CHD screening for a child in Qushui County of Lhasa, capital of southwest China`s Tibet Autonomous Region, April 22, 2022. (Xinhua/Li Jian)

A medical expert carries out CHD screening for a child in Qushui County of Lhasa, capital of southwest China`s Tibet Autonomous Region, April 25, 2022. (Xinhua/Zhang Rufeng)

A medical expert carries out CHD screening for a child in Qushui County of Lhasa, capital of southwest China`s Tibet Autonomous Region, April 25, 2022. (Xinhua/Zhang Rufeng)

A medical expert carries out CHD screening for a child in Qushui County of Lhasa, capital of southwest China`s Tibet Autonomous Region, April 25, 2022. (Xinhua/Li Jian)