
The trigger was a Han Chinese mob attack on Uighur workers at a toy factory in Guangdong province a fortnight ago in which at least two Uighurs died, and the perception that not enough was being done to bring the perpetrators to book.
But what brought out the Uighurs in the Xinjiang capital of Urumqi on Sunday to protest against the incident had deeper roots. Resentment against the Han Chinese had been simmering, possibly made worse by the economic downturn as Uighurs were more likely to lose their jobs before their Han colleagues - particularly if their employers were Han. A woman Uighur protester was heard shouting: "Xinjiang is for Xinjiang people. It does not belong to Han Chinese. Go home!"
Overall, the Chinese government's policy to develop the west, launched nine years ago, has seen rapid economic growth in Xinjiang. Its GDP has grown from 220 billion yuan in 2004 to 415 billion yuan last year, with double-digit growth since 2003. There is now a Uighur middle class.
But if the policy was meant to reduce social tensions, it has failed. For, as in other parts of China, economic development has led to a widening income gap.
In Xinjiang, there is a perception that the Han benefit more than Uighurs from the policy, and not without reason. The better-educated Han Chinese get the choice jobs and greater access to public goods. This breeds resentment of the Han, who do not help matters by their attitude towards the Uighurs. They see themselves as superior to the Uighurs and do not make an effort to understand or mix with them. They are also resentful of affirmative programmes to give Uighurs a leg-up. In the past few days, the Han Chinese have rampaged through Urumqi seeking revenge but also venting their unhappiness.
There is no question that Beijing will bring the situation under control. It is hoped that in going after the rioters, it will be restrained and even-handed, treating Han and Uighurs equally.
Ethnic relations are complex and need tolerance, understanding and a willingness to live and let live on all sides. Han-Uighur relations in Xinjiang have declined in recent years. The government can help by taking measures to increase tolerance and reduce tension. The alternative is yet more ethnic-based clashes.