On Sunday 28 September, Hong Kong exploded. Pro-democracy protesters barricaded major roads, as riot police tried in vain to disperse them with teargas. The former British colony had been tightly wound for months over Beijing’s rising influence. Still, the protests’ scale and intensity came as a shock to many. All it took was one decree – the central government announcing that it would restrict nominations for the city’s next top leader – for the city to unravel.

Hong Kong’s so-called Umbrella Movement raged for more than two months, as umbrella-wielding protesters clashed with riot police. But for many China-watchers, those first few days offered one of the year’s clearest signs: that the country’s economic might and ruthless political machinery mask a deeper insecurity.

“A single spark can light a prairie fire,” Mao Zedong wrote in 1930. Xi Jinping, China’s president, sees sparks everywhere: in the country’s ubiquitous corruption, its polluted water and air, its slowing economy. Whereas Mao kindled them, Xi has spent much of his early tenure trying to stamp them out.

This year, Xi cemented a reputation as China’s most powerful ruler since Deng Xiaoping, primarily by way of his sprawling anti-graft campaign. By September, anti-corruption authorities had netted hundreds of officials for taking bribes, promoting friends and keeping mistresses. Earlier this month they arrested the former security tsar Zhou Yongkang – the highest-ranking official to be investigated for graft in party history.

Simultaneously, Xi presided over the biggest crackdown on freedom of speech in recent memory, posing an important question: can a political system that fostered endemic corruption also root it out? Authorities arrested scores of activists, including the prominent legal scholar Xu Zhiyong. Xu led the New Citizens’ Movement, a grassroots organisation that promoted government transparency. His four-year sentence held a chilling lesson: that nothing trumped the party’s obsession with control, even its own ideals.

Xi also positioned himself as a foreign policy president, often to his neighbours’ chagrin, as China aggressively asserts its territorial claims in the South and East China seas. On 1 May, China placed an oil rig close to Vietnam’s coast, triggering a tense maritime standoff. Weeks later, Vietnamese workers rioted, killing five people and scorching Chinese-owned factories. Relations between the two countries have yet to recover.

China found itself at the centre of another international incident when, in the early hours of 8 March, the Beijing-bound Malaysia Airlines flight MH370 vanished an hour after taking off from Kuala Lumpur. Around two-thirds of the 227 passengers on board were Chinese. Nine months later, despite a massive international search effort, people are still waiting for answers.

China will remember 2014 as a year of terror. On 1 March, black-clad assailants killed 29 people with knives and machetes at a train station in the south-western city of Kunming. The attackers were Muslim Uighurs from north-western Xinjiang. It was – although the region is frequently beset by ethnic violence – the first time Uighurs had been accused of orchestrating a major attack outside the province’s borders.

The country was horrified – state media called the incident “China’s 9/11”. Authorities responded by declaring a “people’s war” against terror, putting much of Xinjiang under virtual martial law. Beijing tightened restrictions on what it considered symbols of religious extremism: beards, veils, fasting during the holy month of Ramadan. Since then, violence has only worsened – in May, an attack on a market in Xinjiang’s capital, Urumqi, killed 45 people. Attacks in Xinjiang’s Shache county killed nearly 100 people on 28 July, and another 15 in November. On 21 September, another attack in dusty Luntai county left another 50 people dead.

In September, authorities sentenced Ilham Tohti, a former economics professor at the prestigious Minzu University of China, to life imprisonment on charges of “separatism”; they confiscated his assets, leaving his wife and two children penniless. Human rights groups called the prosecution of a leading Uighur academic a “travesty of justice” that underscores the government’s unwillingness to field even moderate forms of dissent.

China also cracked down on foreign businesses, raising fears of xenophobia and economic nationalism. Authorities raided many firms, ostensibly for violating a six-year-old anti-monopoly law: Microsoft, Qualcomm, Daimler, Audi, Mercedes Benz, and a dozen Japanese auto-parts makers. They fined the British pharmaceuticals giant GlaxoSmithKline $465m for bribing Chinese doctors and hospital officials to sell its drugs.

Meanwhile, Chinese firms flourished abroad. In October, an obscure Chinese insurance company bought New York’s famous Waldorf Astoria hotel. The Chinese tech giant Alibaba floated on the New York Stock Exchange the month before – the biggest debut in history, with the company valued at $230bn. “We want to be bigger than Walmart,” Jack Ma, the company’s English-speaking founder, said as he rang the NYSE’s opening bell.

June marked the 25th anniversary of the crackdown on pro-democracy protest in Tiananmen Square. Authorities scrubbed all mention of the incident from the internet and detained more than 40 journalists, lawyers, scholars and activists for commemorating the event. Among them was Pu Zhiqiang, the human rights lawyer who once represented the dissident artist Ai Weiwei. Perhaps he and the many other Chinese dissidents detained in 2014 would find some solace in Ma’s words: “Today is cruel,” the entrepreneur famously said in 2004. “Tomorrow will be crueller. But the day after tomorrow will be beautiful. Most people can’t see the day after tomorrow.”