Work has begun on the first phase of the subway system in Shenzhen, the vanguard city in China 's reform and opening-up drive, in south China's Guangdong Province.

The Shenzhen City Subway Company Ltd. and the project contractor have signed an agreement with the Anti-Corruption Bureau of the Shenzhen City Procuratorate, vowing to be honest.

The designing, bidding and building of the subway have all been under supervision, authorities say.

According to the plan, the first stage of the subway will be 19. 468 km long with 18 stations, and will cost an estimated 10.585 billion yuan. It will be completed in four years.

The Shenzhen subway is one of eleven new state-backed key construction projects started this year in China. France's consulting firm Systra has been contracted as a technical advisor for the Shenzhen system.

Subway service is now available in China only in the cities of Beijing, Tianjin, Shanghai, and Guangzhou. In the years to come, more Chinese cities will build subways as a means encouraged by the government for reducing pollution and spurring the national economy.