Chinese customs officers in eastern Shandong province have seized 60,000 maps that 'mislabelled' the self-governed island of Taiwan, which Beijing claims as part of its territory. The maps, authorities said, also 'omitted important islands' in the South China Sea, where Beijing's claims overlap with those of its neighbours, including the Philippines and Vietnam.

The 'problematic' maps, meant for export, cannot be sold because they 'endanger national unity, sovereignty and territorial integrity' of China, authorities stated. Maps pose a sensitive issue for China and its rivals concerning reefs, islands, and outcrops in the South China Sea.

China Customs mentioned that the maps lacked the nine-dash line, a critical demarcation of Beijing's territorial claims over nearly the entire South China Sea. This line stretches hundreds of miles from the southern province of Hainan.

Additionally, the seized maps failed to delineate the maritime boundary between China and Japan. Authorities pointed out that the maps mislabelled Taiwan province, though they did not specify the exact nature of the misrepresentation.

China considers self-ruled Taiwan part of its territory and has hinted at potential military actions to assert claims over the island, while Taiwan regards itself as a distinct nation with its own constitution and elected government officials.

Tensions can flare occasionally in the South China Sea, with recent incidents connected to confrontations between Chinese and Philippine vessels, where Manila accused a Chinese ship of aggressive actions. Beijing, however, claimed the incident occurred after the Philippine vessel disregarded warnings and approached the Chinese ship dangerously.

The Philippines and Vietnam are particularly sensitive to how the South China Sea is depicted in maps. Recent past incidents include the banning of movies for showing maps that include the nine-dash line, which is seen as a provocative depiction of Chinese territorial claims.

The confiscation of these 'problematic maps' is not unprecedented. In previous months, other instances of map seizures occurred where customs officers flagged issues related to national borders and territorial representations.