Celebrations in Shenzhen yesterday to mark the 30th anniversary of the establishment of the mainland's first special economic zone were postponed after President Hu Jintao decided to stay in Beijing in the wake of the Manila bus hostage tragedy. Shenzhen's administration bureau issued an urgent notice postponing a 30-minute fireworks extravaganza outside the government headquarters. A propaganda department spokeswoman said it would take place next month. Officials and political observers said it was wise to cancel big celebrations as Hong Kong struggled to deal with its grief. Shenzhen officials last week said top central and provincial leaders were expected to attend the event.