Chilling footage shows the sky over an Indonesian province turning a dark blood-red colour following a surge of forest fires throughout the country.
In the province of Jambi, on the east coast of central Sumatra, the sky appeared to turn a dark reddish hue, with smoky conditions making it difficult to breathe.
Social media users in Indonesia shared footage of the conditions on Twitter.
"This afternoon is not night," Zuni Shofi Yatun Nisa wrote. "This is earth, not planet Mars. This is not in outer space. It's us who breathe with lungs, not with gills. We humans need clean air, not smoke."
A meteorology expert told the BBC the disturbing footage was caused by a phenomenon known as Rayleigh scattering.
Professor Koh Tieh Yong, of the Singapore University of Social Sciences, said the phenomenon had to do with certain types of particles that were present during a haze period.
"In the smoke haze, the most abundant particles are around one micrometer in size, but these particles do not change the colour of the light we see," he said.
This, combined with smaller particles, are enough to "give an extra tendency to scatter red light more in the forward and backward directions than blue light".
According to the Copernicus Atmosphere Monitoring Service (CAMS), an EU-based weather service that provides data on atmospheric composition, thousands of hectares of ecologically important land are being burned and creating a toxic haze.
Mark Parrington, a senior CAMS scientist, said the organisation is monitoring the intensity of the fires.
"Approximately half of the local fire season having passed, it is clear that these fires are unusual and are causing significant concern," he said. "In Indonesia, burning peat, which can smoulder at low temperatures and underground, is the most significant concern as it is releasing carbon which has been stored for tens or thousands of years."
Similar to the Amazon rainforest fires, the fires in Indonesia were started deliberately in order to clear land for agriculture.