Thick smoke from wildfires caused by illegal land clearing in Indonesia is making thousands of people sick. South Sumatra, one of the main centres of the fires, has reported 22,585 cases of acute respiratory tract infections in the last 24 hours.

Indonesia fires smoke air pollution
Smoke rises from a burning forest at Ogan Komering Ulu area in Indonesia's south Sumatra provinceBeawiharta/Reuters
Indonesia fires smoke air pollution
An Mi-17 helicopter collects water from a canal to be dumped on a forest fire at Ogan Komering Ulu area in Indonesia's south Sumatra provinceBeawiharta/Reuters
Indonesia fires smoke air pollution
A helicopter dumps water on a burning forest at Ogan Komering Ulu area in Indonesia's south Sumatra provinceBeawiharta/Reuters
Indonesia fires smoke air pollution
Haze blankets the Musi River while children travel to school in Palembang, on Indonesia's Sumatra islandBeawiharta/Reuters
Indonesia fires smoke air pollution
Workers carry a hose through a burnt palm oil plantation in Indonesia's South Sumatra provinceBeawiharta/Reuters
Indonesia fires smoke air pollution
A worker uses a motorbike to drag a hose pipe in Indonesia's South Sumatra provinceBeawiharta/Reuters
Indonesia fires smoke air pollution
A worker tackles a burning palm oil plantation at the Pulo Geronggang village in Ogan Komering Ilir district in Indonesia's South Sumatra provinceBeawiharta/Reuters
Indonesia fires smoke air pollution
Residents carry water as they try to extinguish fires near their homes at Pal 7 village in Ogan Ilir district, Indonesia's South Sumatra provinceAntara Foto/Reuters
Indonesia fires smoke air pollution
An Indonesian soldier uses swimming goggles to protect his eyes from smoke while helping to fight a fire in a peatland forest area in Parit Indah Village, Kampar, Riau province, IndonesiaYT Haryono/Reuters

The haze is delaying flights and pushing air quality to unhealthy levels in neighbouring Singapore and Malaysia. Singapore's Pollutants Standard Index rose to 248, which categorises the air as "very unhealthy", or one level below the index's highest air pollution category of "hazardous". Citizens have been advised against strenuous outdoor exercise.

Indonesia fires smoke air pollution
A man reads a book by a pool, as the Petronas Towers are seen in the background shrouded by the haze in Kuala Lumpur, Malaysia
Indonesia fires smoke air pollution
People take photos of the skyline of Singapore's central business district shrouded in hazeEdgar Su/Reuters
Indonesia fires smoke air pollution
The national stadium is shrouded by haze among apartments in SingaporeEdgar Su/Reuters
Indonesia fires smoke air pollution
Buildings are shrouded by haze in Kuala Lumpur, MalaysiaMohd Rasfan/AFP
Indonesia fires smoke air pollution
Houses are partly obscured by haze, as seen from the Hulu Langat hill in Ampang, MalaysiaMohd Rasfan/AFP

Indonesia has said it will send more than 10,000 troops to fight fires in southern Sumatra. Indonesian troops will be sent to the provinces of South Sumatra and Jambi, two of the main hotspots, Indonesia's National Disaster Mitigation Agency (BNPB) said. If necessary, the agency would also send in additional helicopters to help water-bomb fires.

The south east Asian country has vowed before to end the seasonal fires but has failed each time to stop the so-called "haze", caused by slash-and-burn clearances on the islands of Sumatra and Borneo, where large areas of forest are held by pulp and paper and palm oil companies