KUNMING — A new highway in Southwest China's Yunnan province collapsed on the second day after it opened to traffic, killing two people and injuring two at the end of last month.

Experts have said that heavy rain caused the collapse.

Netizens have called the road “the most short-lived highway in history”.

The highway runs from Xinping Yi and Dai autonomous county to Sanjiang county in Yunnan province. Work on it started in October 2009, although Yunnan Provincial Transport Department did not approve the design until May 2010.

Bu Youzhang, the head of Xinping transport bureau, said the two fatalities were employees of the company constructing the highway. One of the injured was discharged from hospital, and the other is still in hospital.

According to Bu, on June 27, a storm over the area where the highway collapsed deposited 60 milliliters of rain in four hours. The torrential rain made the highway surface very slippery and caused rockslides on a nearby mountain.

"The investigation said the project was carried out according to specifications,” Bu said.

"After the accident, the provincial transport department sent three investigators to the scene and they found that the accident was caused by the torrential rain,” said Zhao Guangzeng, an official from the Yunnan Transport Department.

However, one netizen said on his micro blog on Sina.com.cn: “Heavy rain is one reason, but not the main one. The local government should have carefully analyzed the project before building began. Even if the road hadn’t collapsed this time, it would have eventually.”

According to a construction employee, workers often did overtime because of the complex geological environment along the highway and the tight construction deadline.

With a length of 92 kilometers and a cost of more than 20 billion yuan ($3.1 billion), the highway went through several towns and was reportedly open to traffic while still in its test phase. Its official opening was scheduled for June 30.

"We are considering two plans,” Bu Youzhang told China Daily. “One is to build a bridge to replace the destroyed section. The other is to repair the road with a better drainage system.”