Beijing's Forbidden City can be at risk of waterlogging, but it's not because modern technologies and modifications have deteriorated the drainage system, Beijing News Radio reported.

The remarks are in response to a popular online hearsay claiming that the Forbidden City, the royal palace of Ming and Qing dynasties also known as the Palace Museum, has never been flooded throughout its history of 600 years.

Previously, a video claimed to have shown ankle-deep deluge near the Forbidden City's Cining Palace, where the imperial concubine or the dowager used to live. Some netizens have questioned whether modern drainage renovation work have made the system more fragile.

Di Yajing, an official in charge of affairs relating to the site's World Heritage Site status, told Beijing News Radio that the Forbidden City has a complex drainage system.

Rain coming down from roofs was guided to the basement and then to the visible and disguised guts, she said, adding that rainwater would flow from the central of the palace to both sides, and from north to south, due to differences in altitude.

The sewers were dredged once a year in springtime in ancient times and nowadays they are dredged three times a year except in winter, the report said. However, despite the elevated frequency of dredging, it's not modern technology that worsened the efficiency of the drainage system, the report said.

During the dredging process, workers have found modern objects such as plastic bottles and bags, even towels and clothing, it said, adding that these items blocked the disguised guts and clogged the drainage system.

In addition, there are plenty of imperial records that have documented occasions in which the palace was flooded and some roofs or walls were damaged by floodwaters, it said. For example, a rain in 1885 led to floodwaters of about 1 meter deep, it said, adding that every time people would locate the spot of blockage, clean it and the drainage system would function right away.