Look at this photo of Mount Gamkonara in Indonesia erupting on July, 10, 2007. Is this is a "minor" source of "pollution"?
Thousands flee Indonesia volcano
Mount Gamkonora is one of 129 active volcanoes in Indonesia
Thousands of Indonesians have been evacuated from the slopes of a volcano that is spewing out hot ash and smoke in the east of the country.
The alert around Mount Gamkonora, in North Maluku province, has been raised to its highest level amid fears a major eruption could be imminent.
Scientists have reported seeing fire and ash clouds rising as high as 4,000m (13,100ft) since Monday.
Some 8,400 villagers have been moved to special camps away from the volcano.
However, scientists are warning that lava could still reach the camps if there is a large eruption - and have advised residents to wear face masks to protect themselves from the ash clouds.
Some 2,000 people are reported to have chosen to remain within the 8km (five mile) danger zone marked out by officials.
'Ring of Fire'
Activity at the 1,635m mountain rose sharply on Monday, prompting scientists to raise the alert level.
Saut Simatupang of Indonesia's Vulcanological Survey told Reuters news agency that the volcano was spitting out volcanic ash as high as 4,000m at its peak on Monday.
He said there had been less smoke and ash on Tuesday "but that does not mean the volcano is safe".
Mt Gamkonora is the highest peak on the island of Halmahera in North Maluku province, some 2,400km east of the Indonesian capital Jakarta.
It is one of at least 120 active volcanoes in Indonesia, which is part of the Asia-Pacific "Ring of Fire", a series of volcanoes and fault lines stretching from the Western Hemisphere through Japan and South East Asia.