People play football at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Sun Fanyue)

People play football at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Li Ran)

Children attend a table tennis training course during summer vacation at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Li Ran)

Children attend a martial arts training course during summer vacation at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Sun Fanyue)

Children attend a basketball training course during summer vacation at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Li Ran)

Children attend a basketball training course during summer vacation at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Li Ran)

A boy attends a baseball training course during summer vacation at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Li Ran)

Children attend a basketball training course during summer vacation at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Sun Fanyue)

People play football at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Sun Fanyue)

A boy attends a table tennis training course during summer vacation at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Sun Fanyue)

A boy attends a martial arts training course during summer vacation at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Li Ran)

A boy attends a baseball training course during summer vacation at pko Sports Complex in Tianjin, north China, July 23, 2020. Pko Sports Complex, transformed from a former discarded factory, provides facilities as cage football field, basketball gym, table tennis gym and martial arts classroom, providing both sports space for nearby residents and multiple sports training courses for students on vacation. (Xinhua/Sun Fanyue)