Why did China declare sovereignty over a disputed reef in South China Sea?

Business Standard

28-04-2025

This development comes at a time when Philippine and US troops are conducting their annual military exercises, which include preparation for potential South China Sea conflicts
New Delhi
China has declared sovereignty over an uninhabited reef, known as Sandy Cay, in the South China Sea potentially intensifying tensions with the Philippines regarding the disputed area.
Television channel China Central Television (CCTV) reported Saturday that China's coast guard 'implemented maritime control and exercised sovereign jurisdiction' over Sandy Cay in mid-April.
This announcement represents China's most recent declaration of sovereignty in these disputed waters. China has long claimed authority over this area.
This report emerged while Philippine and US troops are conducting their annual military exercises, which include preparation for potential South China Sea conflicts. China has expressed opposition to these war games, claiming they disrupt 'regional strategic stability'. Tensions between China and the Philippines have persisted in the South China Sea, where both nations assert overlapping claims to reefs and small islands.
China bases its claim to the South China Sea on historical grounds, tracing back to records from the Xia and Han dynasties. China defines its territorial claims through the nine-dash line, which was put forward by Chiang Kai Shek in 1947. During China's republican period, China conducted surveys, created maps, and assigned names to 291 islands and reefs in the area. The United States maintains that the South China Sea constitutes international waters and that sovereignty in the region should be determined according to the United Nations Convention on Laws of the Sea (Unclos). Unclos stipulates that nations cannot claim sovereignty over any land formations that are underwater at high tide, or those that were previously submerged but have been artificially raised above high tide level through construction activities.
Hague's ruling over nine-dash line
In 2016, the Permanent Court of Arbitration in The Hague, Netherlands, ruled that China's expansive claims through its nine-dash line lacked legal grounding under international law, granting the Philippines a major victory. However, China, which rejects the ruling, has become more assertive in its actions. Beijing has deployed hundreds of coastguard vessels to patrol the disputed areas, raising concerns for the Philippines, other claimants, and countries operating in the South China Sea, including the United States.
Recent flashpoints in South China Sea
Confrontations between the Philippines and China in the South China Sea have intensified over the past year as Beijing has pushed its territorial claims. Central to recent standoffs between the Philippines and China are two hotly contested features located inside Manila's 200-nautical mile exclusive economic zone, but which Beijing claims as its own.
China uses the nine-dash line that takes in about 90 per cent of the South China Sea to assert its claim to sovereignty over the Scarborough Shoal, a submerged reef coveted for its bountiful fish stocks, and the Second Thomas Shoal, home to a small contingent of Filipino sailors living aboard a rusty warship that Manila intentionally grounded in 1999 to further its territorial claims.
Will the US get involved at South China Sea?
The United States maintains a Mutual Defence Treaty with the Philippines and has repeatedly emphasised that it would defend its ally if its coastguard or armed forces were attacked anywhere in the South China Sea.
The treaty significantly increases the stakes in the Philippines-China dispute should a miscalculation occur at sea. However, Philippine officials, including Marcos, have rejected suggestions of invoking the treaty in the current situation, emphasising that it would be considered only as a last resort.