Beijing is expected to upgrade the drainage systems of all its 78 underpasses by the end of 2015, according to Beijing Drainage Group Co Ltd.

Reconstruction of seven of them has been finished, and the upgrading of the remaining 71 underpasses, which were built lower than the surrounding roads, will begin this year, a report from the company said.

After the work, no vehicles will be submerged when passing through such underpasses in Beijing even when the rainfall reaches 50 cm.

"Different reconstruction plans have been designed for different underpasses," said Liang Yi, an official in charge of pipe network management at the company.

"For example, more powerful pumps will be added if water fails to drain from the underpasses when the rainfall reaches 50 cm."

Data on flooding under the bridges and the performance of pumps will be collected and analyzed by the authority on a video surveillance management platform.

In addition, adjustable reservoirs will be built for some underpasses, which will prevent flooding even if the rainfall reaches 70 cm.