JAMBI PROVINCE, INDONESIA — Wildfires in Indonesia caused the sky to take on an eerie red color over the weekend.

Many took to Twitter to share photos and videos of the blood-red landscape, which looks straight out of an apocalyptic film.

According to the Guardian, forest fires occur annually in Indonesia, usually as a result of using the slash-and-burn method to clear land for palm oil, paper, and pulp plantations. Though technically illegal in the country, the BBC reports that it has been allowed to continue unpunished for years.

The fires create a smoky haze that can end up spreading throughout Southeast Asia, and have caused the skies over Indonesia's Jami province to turn a blood red hue."

Singapore University of Social Sciences professor Koh Tieh Yong told the BBC that the phenomenon is due to Rayleigh scattering — the dispersal of light off of the molecules of the air. This is the same process that makes the sky blue.

According to Professor Koh, certain particles that are around 0.05 micrometers or less are more abundant during a period of haze, and provide an extra tendency to scatter more red light forwards and backwards than blue light.

Looking up around noon, at the direct line of the sun, can also make the sky appear redder.

While the phenomenon won't modify air temperature, the haze levels reported this year is one of the worst, and is affecting millions.

According to Al Jazeera, residents of Jambi have had to wear masks to protect from the toxic smog. Many have reported respiratory problems as a result of the haze.