HANGZHOU - The first metro line in East China's scenic city of Hangzhou will be put into service on Saturday, after more than five years of construction.

The opening of the 48-km-long Metro Line One was delayed after a tunnel collapse one year after construction began in 2007, which caused 21 deaths and left 24 people injured.

Shao Jianming, chairman of the Hangzhou Metro Group behind the project, said on Friday that the 24-billion-yuan ($3.85 billion) line boasts complex technology, as it runs underneath the West Lake, the Qiantang River, the Grand Canal and several railways.

"The construction team had to overcome a lot of difficulties, because of complicated underwater geological conditions such as pebble beds and methane gas," he said.

Incorporating 31 stations, the line will accommodate 48 trains running to ensure a departure every 10 minutes from 6:30 am to 8:30 pm daily. Ticket fares are set to vary from 2 to 8 yuan depending on the distance passengers are traveling.

It will be jointly operated by the Hangzhou Metro Group and the Hong Kong-based MTR, according to a deal signed in July on a 51-49 joint venture to manage the line for 25 years.

The public have been enthusiastic about the opening, which is widely anticipated to ease the city's traffic woes. About 220,000 people, many of them journalists, rode on the trains during test rides organized from Sunday to Wednesday.

Shao said Hangzhou plans to have a metro network eventually boasting 10 lines and comprising 40 percent of the city's public transport.