Beijing’s push to control the South China Sea, marked by increased military presence, has been a bone of contention in Southeast Asia for some months now. While China tries to play ‘big brother,’ neighbours such as Vietnam, Philippines and Malaysia look to the United States for support. With Xi Jinping securing his position as China’s president for years to come, matters are only expected to get worse.Here’s a look at how geo-politics over the crucial sea has played out so far. The South China Sea is a marginal sea that is part of the Pacific Ocean, encompassing around 3,500,000 square kilometres from the Karimata and Malacca Straits to the Strait of Taiwan.The sea bears tremendous strategic importance: one-third of the world’s shipping passes through it, facilitating more than USD 3 trillion in trade each year. It also contains lucrative fisheries that are crucial for the food security of millions in Southeast Asia, and huge oil and gas reserves are believed to lie beneath its seabed.See the map for the exact location of the sea and its surrounding nations.The South China Sea functions as the ‘throat’ of the Western Pacific and Indian Oceans where global sea routes coalesce.The minute South China Sea islands, collectively an archipelago, number in the hundreds. The sea and its mostly uninhabited islands are subject to competing claims of sovereignty by several countries, with China leading the bandwagon. Located at the centre of the South China Sea is a small group of uninhabited island atolls known as the Spratly Islands. Not a day passes without a disturbance shaking the sea violently. For the first time since the end of the Vietnam War, a US aircraft carrier made a port call to Vietnam, in February 2018. The vessel, the Carl Vinson, anchored off Danang, the central Vietnamese port city, with 5,500 sailors aboard. An American warship also sailed near an island claimed by Beijing in the South China Sea on 24 May 2017.After Hague Ruling on South China Sea, ‘Chexit’ Not an OptionNot to be left behind, Chinese President Xi Jinping reviewed the Chinese People’s Liberation Army Navy in the South China Sea in April 2018, saying that the need to build a strong navy ‘has never been more urgent than today’. Taking part in the review were more than 10,000 service personnel, 48 vessels and 76 aircraft, including the aircraft carrier Liaoning.The region is the world's second-busiest international sea lane – more than half of the world's super tanker traffic and 30 percent of all global maritime trade passes through its waters. Tanker traffic through the Strait of Malacca, leading into the South China Sea, is more than three times greater than Suez Canal traffic, and well over five times busier than that of the Panama Canal.Roughly two-thirds of South Korea’s energy supplies, nearly 60 percent of Japan’s and Taiwan’s energy supplies, and 80 percent of China’s crude oil imports come through the South China Sea. The sea is a vital passageway for energy products.Beijing Seen Poised for Fresh South China Sea AssertivenessIn addition, the South China Sea has proven oil reserves of seven billion barrels, and an estimated 900 trillion cubic feet of natural gas. The Chinese believe that the South China Sea will ultimately yield 130 billion barrels of oil.This would mean that the South China Sea contains more oil than any area of the globe except Saudi Arabia. Till date, the China National Offshore Oil Corporation has invested USD 20 billion in the belief that such amounts of oil are present in the South China Sea.This may be because Chinese oil reserves account for only 1.1 percent of the world’s total, while the country consumes over 10 percent of the world’s oil and over 20 percent of all energy consumed on the planet.Brunei claims a southern reef of the Spratly Islands, Malaysia three islands and the Philippines eight islands and significant portions of the South China Sea’s waters. Vietnam, Taiwan and China each claim much of the South China Sea, as well as all of the Spratly and Paracel island groups.These littoral states are, more or less, opposed to China’s claims and dependent upon the United States for diplomatic and military backing. These conflicting claims will become more acute, as energy consumption in developing Asian countries will increase by 2030, with China accounting for half of that growth.In 2017 alone, China built permanent facilities on reclaimed lands that ‘account for about 72 acres, or 290,000 square meters, of new real estate’. China has built concrete helipads and military structures on seven reefs and shoals. It has also constructed a three-story building and five octagonal concrete structures, all for military use.On Johnson Reef, China has built a structure armed with high-powered machine guns. In response, Taiwan now occupies Itu Aba Island, on which it has constructed dozens of buildings for military use, protected by hundreds of troops and 20 coastal guns.Vietnam occupies 21 islands on which it has built runways, piers, barracks, storage tanks and gun emplacements. Malaysia and the Philippines have five and nine sites respectively, occupied by naval detachments.China’s Posturing in South China Sea Makes India, Vietnam UneasyChina has been dredging sand from the ocean floor and extending the size of seven now-occupied reefs. They have constructed three airfields that can support large military transport aircraft. With this, China would be able to control the South China Sea.In 2016, an international tribunal ruled overwhelmingly in favour of the Philippines in a case that questioned China’s vast claims in the South China Sea, but the legal victory has proven largely irrelevant to regional geopolitics as the verdict has not been implemented unilaterally by China. In 2014, Beijing moved an oil-drilling rig into disputed waters. The Vietnamese responded with anti-China protests that killed two Chinese workers.China insists on its ‘indisputable sovereignty’ over the area like a ‘big brother’, but a number of other claimants, such as Vietnam, Brunei, Malaysia and the Philippines, have the law on their side. All have exclusive economic zones (EEZs) in the South China Sea, which is their right under UN Convention of the Law of the Sea, but the Chinese have been dismissing them successfully.United States feels that its deployments in the South China Sea are important for ensuring maritime security and nurturing amicable conditions among the littoral nations. But first the United States has to defend the regional alliance system and offer reassurance to local powers.(Y Udaya Chandar is a retired Colonel from the Indian Army. This is a personal blog and the views expressed above are the author’s own. 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