"Much like Western culture's Halloween, some Eastern cultures celebrate a Fall festival where they believe the gates of hell are thrown open, releasing hungry ghosts to wander the earth in search of food and taking revenge upon those who wronged them in life. This month-long festival is known as the Hungry Ghost Festival and takes place during the 7th lunar month.
Unlike other celebrations of the dead in Eastern cultures that seek to honor dead ancestors, the Hungry Ghost Festival seeks to pacify the hungry ghosts, the ghosts of strangers and the un-cared-for dead. These are the ghosts of those who died by their own hands, by accidents, by drowning or hanging who have been denied entry into heaven. Angry because they are forced to dwell in hell without food or comfort, when released, they search for souls to take their place in misery.
The most important days of this month are the 14th and 15th, the days of the great feasts. On the 14th, a great feast would be held to honor family ancestors. Prayers and offerings would be made at family altars. On the following night, the 15th, they would feast for the hungry ghosts. Held outside under the full moon, these feasts feed the evil spirits so that they will leave the living alone and bribe（贿赂） the ancestors for luck with money and the harvest."
The fireworks was so dangerous that it explode on the land instead of at the sky. If there are ignitable stuff, sure have fire all around the place already.
You can only know how dangerous it is after watch this video.
Audio was muted because the song they use somehow was copyrighted =S