Every year on 10 March, Nyarong Atti spends the day praying for Tibetans around the world. He offers pujas, or prayers, to those who, like him, fled to India after the People’s Liberation Army crushed protesters in Lhasa. The crackdown ended a fledgling rebellion against Chinese rule and sent the Dalai Lama into exile.

Thousands of Tibetans surrounded the Dalai Lama’s palace in Lhasa 60 years ago on Sunday, fearing a Chinese plot to kidnap or assassinate the leader. Chinese forces had occupied the Himalayan region nine years earlier and formed an uneasy alliance with the Dalai Lama, but tensions had been building.

By 17 March 1959 Chinese artillery was aimed at the palace, and a few days later troops opened fire, killing thousands. By the end of the month, China had dissolved the Tibetan government and the Dalai Lama had escaped, smuggled out of the city disguised as a Chinese soldier.

For Atti, 87, who was among those fighting against Chinese rule, the anniversary brings a mix of emotions, chief among them anger and sadness. “Tibet was completely taken over by China and many people died,” he says.

Hundreds of supporters of the 14th Dalai Lama surrounded his temple in Dharamsala in India on Sunday, home to his government in exile since 1959. Supporters elsewhere planned marches to commemorate the failed uprising and call attention to what they describe as a brutal campaign of suppression.

Chinese authorities have tightened their hold on Tibet, which Beijing claims has always been part of China. Local officials have instituted a “grid” system of security through a vast network of “convenient police stations”, checkpoints and the use of mass surveillance. Tibetans often cannot travel freely in and out of the region and their communication is often monitored.

“Tibet today is effectively run as a huge open-air prison,” said John Jones, a campaigns manager at Free Tibet, an advocacy group. “Any sign of dissent, from flying the Tibetan flag to possessing pictures of the Dalai Lama … is treated as a state security crime. The level of state control has been stepped up to the point of being suffocating.”

Local authorities have banned monasteries in Tibetan areas, a key source of education in the region, from teaching for fear of “ideological infiltration among the young”, according to a notice in Qinghai province found by Human Rights Watch. Last year a language activist named Tashi Wangchuk was sentenced to five years in prison for “inciting separatism”.

Beijing defends its policies in Tibet, saying it ended a backwards, feudalistic system and brought economic development to a region where most families relied on livestock and agriculture. An editorial on Saturday by the state news agency Xinhua said: “Sixty years since the epoch-making democratic reform in Tibet, people in the plateau region have enjoyed unprecedented human rights.”

Yet discontent has continued. Anti-Chinese riots broke out again on 14 March 2008, and since then more than 150 Tibetans, mostly monks, have set themselves on fire in protest.

Facebook Twitter Pinterest Chinese military patrol the streets in Lhasa on 15 March 2008, a day after violent protests against Chinese rule. Photograph: AFP/Getty Images

Security has been stepped up before the sensitive month of anniversaries. Atti, who still has relatives in Tibet, has not been able to call them for several weeks. The Lhasa police posted on 5 March about a citywide search for potential threats to stability that involved the entire police force “united in iron will”.

The post on Weibo included photos of police squadrons at different places in the city, lines of police cars, and searches of what appear to be Tibetan homes and establishments, as well as hotels, internet bars and shops. In Lhasa, 200 taxis have been equipped with facial recognition technology, according to a report last week.

Foreigners, who need a special permit to travel to the Tibetan Autonomous Region, are banned for the month of March, a policy that has been in place since the 2008 riots. Three travel agencies told the Guardian they could not take foreigners to the region this month, while two said they could do so only if none of the travellers were journalists. Chinese officials have attributed the restrictions on foreigners and journalists to Tibet’s high altitude.

Facebook Twitter Pinterest Nyarong Atti and family

For Atti, now living in a village in the northern Indian state of Himachal Pradesh, following the news of what is happening in his homeland is difficult. He feels the familiar mix of sadness and anger, but also helplessness. “I can’t do anything about it,” he says.

Born in eastern Tibet, also known as Kham, Atti joined fighters resisting the Chinese in 1956, at the age of 24. He was travelling to Lhasa in May 1959 when he heard that Chinese forces had taken the city and that the Dalai Lama had fled to India. News travelled slowly then, he notes. “I was very happy and my first thought was that we could have a better future.”

He trekked to Nepal and eventually to India. His parents, brother and three sisters, who also attempted to flee, all died along the way. After years of fighting, he now lives a simple life, spending most of his time at home, doing his prayers, video chatting with his grandchildren who live in England, or talking with neighbours who stop by.

But if he could have continued to fight, he would. “They took my land, my wealth, my family, my mum and dad – everyone – from me,” he says. “As long as my body gives me strength, I would always fight.”