In 100 days' time, China's Olympics will be under way, but people from film stars to football coaches are not happy.

Owen Amos gives five reasons to boycott Beijing - and three reasons not to

DARFUR

WHEN Steven Spielberg complains, you know you're in trouble. Spielberg, director of ET, Jurassic Park, and Schindler's List among others, was due to be artistic advisor for the Beijing Olympics. However, he pulled out in February, citing China's role in the humanitarian disaster in Darfur, Sudan. "I find that my conscience will not allow me to continue business as usual," he said.

The Sudanese government supports one side, largely Arab, in a civil war against another side, largely non-Arab. The UN says up to 400,000 people have been killed by violence and disease and Colin Powell, then US Secretary of State, said genocide had taken place.

Since 1993, China has been a net oil importer. It buys two-thirds of Sudan's oil, helping to prop up that regime. In turn, Sudan buys its weapons from China. A Council on Foreign Relations report said China supplied Sudan with small arms, anti-personnel mines, howitzers, tanks and helicopters.

China says "political means" should solve the issue. Spielberg says: "Sudan's government bears the bulk of the responsibility but the international community, and particularly China, should be doing more."

TIBET

WHO owns Tibet? Tibet has been part of China since the 13th Century, the Chinese government says. Some Tibetans disagree. They claim Tibet declared itself independent in 1912, after Chinese troops there surrendered. On October 7, 1950, China invaded Tibet, forcing a surrender 12 days later. The 17-Point Agreement, signed by China and Tibet in 1951, confirmed Tibet as part of "the motherland".

However, after a failed uprising in 1959, the Dalai Lama repudiated the 17-Point Agreement and fled to India to form the Tibetan Government in Exile.

The Dalai Lama does not object to Chinese rule, but demands far greater autonomy.

In March this year, Buddhist monks marched to commemorate the 49th anniversary of the uprising.

Security forces arrested some marchers, prompting more anti-China protests - this time about economic conditions and Chinese immigrants, as well as independence. Some protestors were shot. The Government in Exile says at least 99 people have died in the Chinese crackdown. Towns were sealed off and foreign journalists banned from entering.

The lockdown sparked sympathy protests worldwide.

Nancy Pelosi, Speaker of the US House of Representatives, said: "If freedom-loving people throughout the world do not speak out against China and the Chinese in Tibet, we have lost all moral authority to speak out on human rights."

POLLUTION

CHINA overtook the US last year as the biggest producer of carbon dioxide, pumping out around 6,200 million tonnes - more than ten times that of the UK.

Last year, a British government climate change official said China builds two coal power stations a week. The subsequent smog around Beijing has caused several athletes to change their plans.

Haile Gebrselassie, the marathon world record holder, is unlikely to run the race due to pollution's threat to his asthma. "It would be difficult for me to run 42km in my current condition," he said. Tennis player Justine Henin has voiced similar fears.

The British Olympic Association spent up to £30,000 developing an anti-smog mask, but recently revealed it is not sure it works. Speaking about smog, Marco Cardinale, of the British Olympic Association, said: "It is very unlikely we'll see outstanding performances in endurance sports".

HUMAN RIGHTS

IN 2001, the Beijing Olympic bid said giving China the games would "help the development of human rights". According to an Amnesty International report, the Chinese record shows "little sign of improving".

Abuses and alleged abuses are widespread.

China executed 470 people in 2007, more than any country in the world. But, according to Amnesty International, the actual figure is in the thousands.

More than 60 crimes carry the death penalty, including tax fraud and stealing VAT receipts. The number of official executions, though, is falling.

There is little freedom of religion in China.

Roman Catholicism is officially banned and Christians must worship with one of two state-approved churches. Last Christmas, a BBC reporter in Beijing wrote: "At an underground church service in China, you pray as quickly as you can - and hope the police do not come running in." Falun Gong - a spiritual practice of meditation that has a reported 70 million followers - was banned in 1999, apart from in Hong Kong and Macau. Followers are routinely arrested.

China has had a one-child policy since 1979, designed to ease pressure on infrastructure by limiting the burgeoning population. The government says it has prevented 400 million births; Chen Guangcheng, a blind activist, was jailed last year for exposing forced abortions.

FREEDOM OF SPEECH

CHINA has enforced a mass block on some websites - dubbed "the Great Firewall of China". The BBC's English language site was unblocked last month, causing Chinese hits to rise from 100 a day to 16,000.

The Chinese language site has been blocked since its launch in 1999. During the Tibet unrest, the Times and Guardian websites and YouTube were blocked.

Journalists at the national broadcaster, CCTV, are told how to report stories, and what not to report.

In the past six months, journalists were warned off a health scandal and told how to report Benazir Bhutto's death. Reporters Without Borders, the press freedom organisation, claims 30 journalists are currently detained by Chinese forces.

Zhao Yan, a New York Times researcher in China, was tried in 2006 for fraud and divulging state secrets.

He was acquitted of the latter charge, but jailed for three years for the former. Journalist Huang Jinqiu was arrested in September 2003 after revealing plans to form a new political party. He was sentenced to 12 years in prison for "subversion"

- a catch-all term used to try thousands of Chinese dissidents - and, according to Amnesty International, has suffered beatings and sleep deprivation.

THREE REASONS NOT TO BOYCOTT

FAIRNESS: China was elected to host the Olympics by the 196 members of the International Olympics Committee. That democratic decision should be upheld.

SPORT: The Olympics is about sport, not politics.

To force boycotts would mean athletes' four-year preparations count for nothing.

CHINESE PEOPLE: The Chinese population has been anticipating hosting the world's biggest event for seven years. To punish 1.3 billion people for their leaders' mistakes would be unfair.