The cloud of smoke produced by wildfires last year probably caused more than 100,000 premature deaths in Southeast Asia, reveals a study by researchers at Harvard and Columbia universities, reports the Guardian.

Researchers have identified over 90,000 premature deaths in Indonesia and thousands in Singapore and Malaysia.

“If nothing changes, this killer smog will generate new and new victims, every year. The refusal to take urgent measures to stop human losses is similar to crime,” said Yuyun Indradi, a representative of Greenpeace Indonesia.

The Indonesian Ministry of Environment has not yet commented on the study findings. Earlier, Indonesian authorities announced intensifying efforts to prevent vegetation fires. Fires occur mainly on the islands of Sumatra and Borneo, the smoke being carried by the wind to Singapore and Malaysia.

This “revolutionary” study performed for the first time provides a number of deaths attributed to forest fires in 2015 but it is a “conservative estimate”, according to Greenpeace.

Only the impacts on adult health and hazardous effects of fine PM 2.5 particles that can reach the deepest branching airways were counted. The effects of the young or other toxins from the fire were not examined.

About 2.6 million hectares of tropical forests in Indonesia turned into ashes last year after some fires were set up especially for deforestation and illegal land fertilization, in particular, to increase the palm oil dedicated plantations.

Dense smoke invaded several countries in Southeast Asia and caused tens of thousands of respiratory infections among the population and the closure of schools and cancellation of many air flights.

Forest fires took place in 2016 in Indonesia, especially on the islands of Sumatra and Kalimantan, but for the moment, the impact appears to be significantly lower than in 2015, mainly due to large amounts of unusual rainfall recorded during the dry season.