In pictures: Indonesia fires

A villager stands on an oil well as fire burns a palm-oil plantation in haze-hit Bangko Pusako district in Rokan Hilir, Indonesia's Riau province, June 22

Forest fires in Indonesia's Sumatra island have shrouded parts of Malaysia, Singapore and the island itself in a choking haze.

Villagers standing beside on an oil pipe are silhouetted by flames burning a palm-oil plantation in Bangko Pusako district, Riau province, June 22

Palm-oil firms are accused of using slash-and-burn agricultural techniques to clear space for plantations.

People wear surgical masks as they ride motorcycles in Dumai, Indonesia's Riau province, June 22

Much of the media's attention has been focused on Singapore, where pollution indexes recorded their worst-ever readings this week, but villagers in Indonesia's Riau province are among the worst hit.

Air pollution indicator in the provincial capital of Riau, Pekanbaru, 22 June

Residents of Riau's provincial capital Pekanbaru are closely watching pollution indicators.

Workers load sacks of salt that will be used for cloud seeding to induce rain in Pekanbaru, Riau province, June 22

Indonesia has mobilised planes and helicopters to battle the fires, and is attempting to induce rain through cloud seeding.

A villager looks at a burning palm oil plantation from Bangko Pusako, Riau province, June 22

Singapore's authorities say they are considering legal action against two Singapore-based firms allegedly linked to some of the fires.

Smoke billows from a forest fire in Pekanbaru, Riau province, June 22

However, the fires and the haze are annual events, and the authorities in Indonesia have shown little inclination to discipline the companies involved.