T.M. Alamsyah, head of the Environmental Impact Management Agency in Riau province, warned Wednesday that smog triggered by the illegal fires had reached an alarming level in Riau and other Sumatran provinces.
``We have found 163 fire spots in Riau alone as of Monday. Now, fire spots are also being detected in the provinces of North Sumatra, Jambi and Lampung,'' Alamsyah said.
Antung Deddy of the Environmental Management Agency (Bapedal) said evacuations may be necessary in some areas along the border of Riau and North Sumatra because pollution has reached very dangerous levels.
``The ISPU (air pollution index) reached 397 Saturday. That means that residents must get ready to wear masks. If rains do not fall in the next few days and there are no signs of the fires subsidizing, we may have to evacuate the residents,'' Deddy said.
An official at the Forestry and Plantations Ministry told Reuters that most of the fires had been started deliberately, mostly by oil palm plantations as a cheap way to clear land.
Indonesia has played down fears the fires would cause a repeat of Southeast Asia's smog crisis in 1997, but also admitted there was no strategy for extinguishing the blazes.
More than 12.35 million acres of forest, plantation and land in Indonesia were razed by fires in 1997.
The resulting smog blanketed large swathes of Indonesia, neighboring Singapore and parts of Malaysia for weeks. It also spread to Thailand and the Philippines.