
Photo taken on Nov. 6, 2021 shows the Cat Linh station in Hanoi, Vietnam. Authorities of the Vietnamese capital Hanoi inaugurated the China-built Cat Linh-Ha Dong metro line project on Saturday, making it the first metro line in the country to start commercial operation. The project was handed over to Hanoi by its investor, the Vietnamese Ministry of Transport, on the same day. Photo: Xinhua

Photo taken on Nov. 6, 2021 shows a train running on Cat Linh-Ha Dong metro line in Hanoi, Vietnam. Authorities of the Vietnamese capital Hanoi inaugurated the China-built Cat Linh-Ha Dong metro line project on Saturday, making it the first metro line in the country to start commercial operation. Photo: Xinhua

Photo taken on Nov. 6, 2021 shows the Cat Linh station in Hanoi, Vietnam. Authorities of the Vietnamese capital Hanoi inaugurated the China-built Cat Linh-Ha Dong metro line project on Saturday, making it the first metro line in the country to start commercial operation. Photo: Xinhua

Photo taken on Nov. 6, 2021 shows a train running on Cat Linh-Ha Dong metro line in Hanoi, Vietnam. Authorities of the Vietnamese capital Hanoi inaugurated the China-built Cat Linh-Ha Dong metro line project on Saturday, making it the first metro line in the country to start commercial operation. Photo: Xinhua

Passengers take photos on a train on Cat Linh-Ha Dong metro line in Hanoi, Vietnam, Nov. 6, 2021. Authorities of the Vietnamese capital Hanoi inaugurated the China-built Cat Linh-Ha Dong metro line project on Saturday, making it the first metro line in the country to start commercial operation. Photo: Xinhua

Young ladies pose for a photo with a train at Cat Linh station in Hanoi, Vietnam, Nov. 6, 2021. Authorities of the Vietnamese capital Hanoi inaugurated the China-built Cat Linh-Ha Dong metro line project on Saturday, making it the first metro line in the country to start commercial operation. Photo: Xinhua

Photo taken on Nov. 6, 2021 shows a train running on Cat Linh-Ha Dong metro line in Hanoi, Vietnam. Authorities of the Vietnamese capital Hanoi inaugurated the China-built Cat Linh-Ha Dong metro line project on Saturday, making it the first metro line in the country to start commercial operation. Photo: Xinhua