Police in Indonesia say eight farmers have been arrested for setting illegal fires in Sumatra.

The smog drifting across South East Asia has been blamed on farmers using a "slash and burn" method to clear land for palm oil plantations.

The Indonesian president, Susilo Bambang Yudhoyono, has issued a public apology and sent reinforcements to the firefighters in Sumatra.

Rupert Wingfield-Hayes reports on how demand for palm oil is driving the fires.