Jakarta. A recent study by Harvard University and Columbia University researchers estimated there were 100,300 premature deaths across Indonesia, Malaysia and Singapore last year caused by haze from wildfires in Indonesia's Sumatra and Kalimantan.

Air pollution readings and satellite data for forest fire smoke exposure indicated toxic emissions in 2015 lead to 2,200 premature deaths in Singapore, 6,500 in Malaysia and 91,600 in Indonesia, making the Indonesian government's official announcement of 19 deaths a serious understatement.

According to the study, peatland fires accounted for 72 percent of emissions in Sumatra and 43 percent in Kalimantan.

"As last year's fires raged, the Indonesian government said 43 million people across the country were exposed to smoke and half a million suffered from smoke-related respiratory complications. Now that we know the scale of the haze death toll, a failure to act immediately should be considered a crime," Greenpeace Indonesia forest campaigner Yuyun Indradi said in a statement on Monday (16/09).

With the haze once again returning this year, the government must step forward and take firm action against forest clearing and peatland drainage for plantations, Yuyun said.

While the Harvard-Columbia study was focused on mortality rate due to the 2015 haze crisis, it also claimed chronic respiratory problems and coronary heart problems are the main health hazards associated with wildfires. Particularly vulnerable are children and pregnant women. A prolonged toxic haze exposure may lead to fetal death.

The Indonesian Medical Association (IDI), meanwhile, urges all parties to combat wildfires considering the fatal health risks posed by their lingering haze.

"What is at stake is the health of Indonesia's future citizens — the most vulnerable groups are the elderly, pregnant women and especially children," Nursyam Ibrahim of the association's West Kalimantan chapter said.

The haze crisis of 2015 brought the world's attention — and a lot of criticism — to Indonesia as wildfires in Sumatra and Kalimantan contributed 3 percent of the global greenhouse gas emissions in 2015, with six provinces declaring a state of emergency on account of the haze.

The World Bank estimated the economic and environmental losses from the 2015 haze crisis amounted to more than $16 billion with 2.6 million hectares of forest .