China has completed a 10-km-long tunnel after six years of work by nearly 1,000 construction workers.

It will allow a major railway to reach countries belonging to the Association of Southeast Asian Nations (ASEAN).

The Xiushan tunnel is located in southwest China's Yunnan Province.

It is listed as a first-level high-risk tunnel due to complicated geological conditions in the region.

It will be pivotal for the construction of the 141-km Yuxi-Mengzi Railway, which is part of the eastern section of the planned Pan-Asia international railway project.

The railway is being built with a total investment 703 million U.S. dollars.

It is expected to become operational later this year, and will boost land transportation between China and ASEAN countries.