While people living in older city areas are often irked by the frequent digging up of roads for underground pipe and cable maintenance, those in Hengqin New Area are free of this trouble, as all the utility facilities are placed in a large underground tunnel.

The 33.4 kilometer comprehensive utility tunnel, one of the largest in the country, houses electricity and telecommunications cables, and pipes for water supply, reclaimed water, air cooling and vacuum garbage transport.

About three meters high and five meters wide, the tunnel has room for more pipes and cables as public services expand, said Yan Lisheng, an engineer of Zhuhai Da Hengqin Urban Public Resources Management Co.

Though the investment for the tunnel sounds high, 2 billion yuan ($321.97 million), the project helps save 40 hectares of land, or 56 football fields, which can be used for greater economic gains, Yan said. The cost is exceptionally high due to the soft roadbed on the island.

A monitoring room with multiple screens is located above the tunnel. The tunnel makes it easier to maintain the pipes and cables and helps extend their life span, saving the spending by pipe owners in building underground facilities by themselves.

"The project is an example of the goal of Zhuhai government to build Hengqin into an ecological-friendly island," Yan said.

The world's first such tunnel appeared in Paris in 1833 and the first in China extended under the Tiananmen Square in 1958.

At least 10 cities, including Shanghai, Shenzhen and Chengdu, have built such utility tunnels, which total 10 km or 20 km and no more than 100 km in each city, said Li Hongyu, a researcher with the Institute for Urban and Environmental Studies of the Chinese Academy of Social Sciences.

The country remains in the preliminary stage in this respect, with some of the tunnels built being used and some not planned well. Future investment into this sector will be huge, Li said.

Such utility tunnels are an important part of urban modernization and a surge in such construction is expected in large cities in the future, Huang Shunjiang, Li's colleague, said.

That construction will also need huge amounts of capital, which is estimated by certain institutions to be about 400 billion to 500 billion yuan. It will help expand domestic demand, Huang said.

The Ministry of Housing and Urban-Rural Development organized a training session in Zhuhai last month for some provincial and city government officials on the planning and construction of such tunnels.

They can be deployed in all new urban areas and built in old city areas according to the actual situation, Minister of Housing and Urban-Rural Development Chen Zhenggao told the training session.

There has been criticism from the public that local governments have placed emphasis on the buildings above the ground but not as much on the facilities underground, which sometimes disrupt life and lead to serious accidents.

The national plan for new-type urbanization for 2014-2020 required that such tunnels be constructed under new roads, new city areas and various parks.

The State Council issued last year a guideline for strengthening the construction and management of such tunnels, with 36 cities to be included in a trial and to receive subsidies from the central government.

"Sewage pipes and underground pipe networks reflect the competitiveness of a city and the responsibility of the city administrators," Chen said.

The tunnel in Hengqin was financed by State-owned Zhuhai Da Hengqin Investment Co, which is responsible for infrastructure construction in the area, and is managed by its subsidiary Zhuhai Da Hengqi Urban Public Resources Management Co.

Owners of the pipes and cables pay for the tunnel service and financial leasing may be introduced in the future for better financial management, said Niu Jing, director of the administrative committee of Hengqin New Area.

The draft regulation on the protection and management of the tunnel in Hengqin for public opinion has been completed.

The tunnel operator worked with the Ministry of Housing and Urban-Rural Development in drafting a guideline for the operation and maintenance of such tunnels.

The engineering and technological standards will be released this month, Chen said.

Technical standards are important because different pipes and cables need different underground environment. The tunnels need to be equipped with a pre-warning system and properly monitored and maintained since gas, water and electricity facilities may potentially cause accidents, Li Hongyu said.