The photos and videos look like something out of science fiction. Social media users in parts of Indonesia shared images of disturbingly blood-red skies over the weekend, and the BBC reports widespread fires in the country caused the unnerving views.
"This is Earth, not planet Mars," said one Twitter user sharing a video.
Thousands of acres are on fire in Indonesia, the Copernicus Atmosphere Monitoring Service said in a statement issued Friday.
"It is believed the fires have been started deliberately in order to clear land for agriculture, in particular for paper and palm oil," the statement said. The UK-based service has recorded data showing that "the daily estimated equivalent CO2 emissions are reaching a similar level to the devastating fires in the same period in 2015."
In a tweet, the service noted that the fires pose "threats to the health of the local population and to wildlife." Indonesia's president, Joko Widodo, urged residents not to set fires and to put out new blazes.
Fires like these are not new to Indonesia, but this year's are exceptionally bad, the Copernicus Atmosphere Monitoring Service reports.
"Approximately half of the local fire season having passed, it is clear that these fires are unusual and are causing significant concern," the service said. "In Indonesia, burning peat, which can smolder 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."
"Pray for Jambi," wrote one Twitter user.
The startling skies are likely caused because of a phenomenon called Rayleigh scattering, Newsweek notes. Because of the way particles in the smoke scatter sunlight, more red light comes through than the normal blue.