Passengers visit Haishan Station of Shenzhen Subway Line 8 before its launch in Shenzhen, south China's Guangdong Province, Oct. 28, 2020. Four new sections of subway went into operation in Shenzhen on Wednesday, extending the total length of the city's metro system to 411 kilometers. (Xinhua/Mao Siqian)

Passengers sit in a train of Shenzhen Subway Line 8 in Shenzhen, south China's Guangdong Province, Oct. 28, 2020. Four new sections of subway went into operation in Shenzhen on Wednesday, extending the total length of the city's metro system to 411 kilometers. (Xinhua/Mao Siqian)

Children learn about Shenzhen Subway Line 8 at Yantiangang Station in Shenzhen, south China's Guangdong Province, Oct. 28, 2020. Four new sections of subway went into operation in Shenzhen on Wednesday, extending the total length of the city's metro system to 411 kilometers. (Xinhua/Mao Siqian)

Passengers wait for a train at Liantangkouan Station of Shenzhen Subway Line 2 in Shenzhen, south China's Guangdong Province, Oct. 28, 2020. Four new sections of subway went into operation in Shenzhen on Wednesday, extending the total length of the city's metro system to 411 kilometers. (Xinhua/Mao Siqian)

A journalist visits Haishan Station of Shenzhen Subway Line 8 before its launch in Shenzhen, south China's Guangdong Province, Oct. 28, 2020. Four new sections of subway went into operation in Shenzhen on Wednesday, extending the total length of the city's metro system to 411 kilometers. (Xinhua/Mao Siqian)

A staff member gives instructions as passengers enter Haishan Station of Shenzhen Subway Line 8 in Shenzhen, south China's Guangdong Province, Oct. 28, 2020. Four new sections of subway went into operation in Shenzhen on Wednesday, extending the total length of the city's metro system to 411 kilometers. (Xinhua/Mao Siqian)

A launching ceremony of new lines of Shenzhen Subway is held at Yantian District of Shenzhen, south China's Guangdong Province, Oct. 28, 2020. Four new sections of subway went into operation in Shenzhen on Wednesday, extending the total length of the city's metro system to 411 kilometers. (Xinhua/Mao Siqian)

People visit Shenzhen Subway Line 8 before its official launch in Shenzhen, south China's Guangdong Province, Oct. 28, 2020. Four new sections of subway went into operation in Shenzhen on Wednesday, extending the total length of the city's metro system to 411 kilometers. (Xinhua/Mao Siqian)