Green groups and health experts have called on the Indonesian government to do more to tackle forest and peatland fires after a study estimated more than 100,000 people died prematurely last year when deadly haze blanketed Southeast Asia.
The report by researchers from Harvard and Columbia universities published in Environmental Research Letters on Monday estimated the haze resulted in 100,300 excess deaths across Indonesia, Malaysia and Singapore last year - much of which was due to fires in Indonesia's South Sumatra province.
The thick smoke which blanketed the region during September to October was likely the "worst haze episode" since 1997, with a combination of conditions - including El Nino - promoting drought and thus allowing fires to spread out of control, the report states.
Comparing it to a similar event in 2006 - the report states smoke-related mortality was almost three times higher.
An estimated 91,600 people died in Indonesia, while a further 6500 died in Malaysia, and 2200 in Singapore.
While the underlying triggers were similar across the extreme haze events of 2006 and 2015 - the report states global markets for palm oil, pulpwood and timber and increases in small-scale agriculture was "evolving rapidly".
Greenpeace Indonesia forest campaigner Yuyun Indradi said it highlighted the need for the government to stop forest clearing and peatland drainage for plantations.
"If nothing changes, this killer haze will carry on taking a terrible toll, year after year," he said.
Dr Nursyam Ibrahim, Deputy of the West Kalimantan chapter of the Indonesian Medical Association, meanwhile, called on all parties to work together to prevent further fires, especially in peatlands.
"The greatest impact from breathing particles from peat fire smoke falls on vulnerable groups such as the elderly, pregnant women, babies and children."
The figures released in the report are dramatically at odds to that put out by the Indonesian government.
According to Indonesia's National Disaster Management Board, 19 people died as a result of the fires and smoke related illness between July and November last year.
Meanwhile, 503,874 people suffered acute respiratory tract infections.
