(CNN) Dozens of people have been arrested over suspected involvement in massive forest fires in Indonesia, where thousands of hectares of ecologically rich land have been burned, engulfing the region in a thick toxic haze.

The country's National Police spokesman Dedi Prasetyo said Monday that 185 people had been arrested across six provinces hit by fires and four corporations were under investigation. He added that "99% of the forest and land fires occurred due to human factors."

Fires and ensuing smog are a persistent problem during the summer months caused by slash and burn techniques to clear the land -- the same practice that led to fires in the Brazilian Amazon earlier this year.

As of this year, more than 328,000 hectares (about 800,000 acres) of land have been burned, hundreds of residents evacuated, and more than 9,000 personnel have been deployed to battle the flames, according to Indonesia's National Board for Disaster Management.

Motorists commute on a hazy day in Palembang on September 18, 2019.

The fires have impacted the lives of people across the region. Singapore and Malaysia have both choked in a dense haze all week as a result of the fires, with air quality reaching unhealthy levels.

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