A staff member of Beijing Emergency Medical Center shows an automated external defibrillator (AED) in Beijing, capital of China, Oct. 27, 2020. Beijing started to equip its rail transit system with AED on Tuesday. By the end of 2022, all stations of the city's rail transit will be equipped with AED. (Xinhua/Zhang Chenlin)

A staff member of Beijing Emergency Medical Center shows an automated external defibrillator (AED) in Beijing, capital of China, Oct. 27, 2020. Beijing started to equip its rail transit system with AED on Tuesday. By the end of 2022, all stations of the city's rail transit will be equipped with AED. (Xinhua/Zhang Chenlin)

An automated external defibrillator (AED) is seen in Xidan Subway Station in Beijing, capital of China, Oct. 27, 2020. Beijing started to equip its rail transit system with AED on Tuesday. By the end of 2022, all stations of the city's rail transit will be equipped with AED. (Xinhua/Zhang Chenlin)

An automated external defibrillator (AED) is seen in Xidan Subway Station in Beijing, capital of China, Oct. 27, 2020. Beijing started to equip its rail transit system with AED on Tuesday. By the end of 2022, all stations of the city's rail transit will be equipped with AED. (Xinhua/Zhang Chenlin)