As the investigation over a recent deadly road collapse continues, an expert warns that more such accidents may happen because of the country's increasingly aging underground pipe network if precautionary measures are not taken in a timely manner.

The accident occurred on Monday evening in Xining, capital of Qinghai province, as people were getting on and off a public bus. The sudden collapse left so large a sinkhole that the bus sank halfway into the ground, and some people at the bus stop also fell into the hole.

A second collapse and an explosion occurred when some people tried to rescue those trapped in the hole. Rescuers had found the bodies of nine victims as of Tuesday, and 16 people have been hospitalized.

A team dispatched by the Ministry of Emergency Management has arrived in Xining to facilitate the investigation of the initial collapse. While no official conclusion has been made over its cause, multiple media reports point out that the collapse could possibly have been triggered by a broken water pipe.

The accident is just the latest example of the increasingly frequent road collapses in the country's urban areas. According to a report concluded by the Beijing Comprehensive Management Research Center of Underground Pipeline and the Underground Pipeline Committee－part of the China Association of City Planning－a tally based on media reports shows that the country saw at least 142 road collapses from October 2018 to September 2019.

Liu Huizhong, executive secretary-general of the committee, said the country's aging underground pipe network is one of the culprits behind the frequent collapses, though some were also caused by natural means.

China buried its first large batch of underground pipes after 1979, and many of the pipes have been aging, Liu noted.

But the country has yet to make marked progress in repairing or strengthening these pipes despite that fact that the government has known the general situation of underground pipes, Liu said. In addition, there are existing technologies to repair these pipes.

As required by a guideline published by the State Council in 2014, a three-year comprehensive survey of pipe networks under main urban roads has been rolled out in order to assess the situation of underground pipes, and the survey has been completed.

The latest technologies have been advanced enough to repair underground pipes without digging into the ground and disturbing the traffic. The service life period of the aging pipes could be extended for another 50 years by adding internal liners via wells constructed especially for pipe maintenance, he added.

Liu said there are currently 750,000 kilometers of underground water pipes across the country, but only about 800 km of them were repaired with such technologies last year.

He also called on the government to ramp up efforts in repairing the pipes and take more precautionary measures.

"With the aging of the country's underground pipe network and the increase of urban construction projects, instead of taking emergency measures after an accident happens, the government should take more precautionary measures," he said.