The haze blanketing swathes of the island archipelago are caused by open burning, which usually peaks from July to October during Indonesia’s dry season. According to Indonesia’s national disaster agency, 328,724 hectares of land were burnt in the first eight months of the year. Part of the blame for the haze lies with big corporations as well as small-scale farmers, who take advantage of the dry conditions to clear vegetation using the slash-and-burn method.
This slash-and-burn technique is the easiest way for farmers to clear land and helps them get rid of disease that may have affected their crops.
However, the fires often spin out of control and spread into protected forested areas.
Slash-and-burn is illegal in Indonesia but has been allowed to continue for years, with some saying corruption and weak governance have contributed to the situation.
This year’s haze levels have been some of the worst in years.
These extraordinary images were captured by a local in Jambi, and show a phenomenon known as Rayleigh scattering.
Eka Wulandari, from the Mekar Sari village in Jambi province who took the pictures, said the haze had “hurt her eyes and throat”.
She shared the photos on Facebook, where they went on to be shared more than 34,000 times.
Some accused her of publishing fake photos, but she told BBC Indonesia: “It’s true. [It’s a] real photo and video that I took with my phone.”
Another Twitter user posted a video showing similarly coloured skies.
The poster, Zuni Shofi Yatun Nisa, wrote: “This is not Mars. This is Jambi.
“We humans need clean air, not smoke.”
Indonesia meteorological agency BMKG said satellite imagery revealed numerous hot spots and “thick smoke distribution” in the area around the Jambi region.
Professor Koh Tieh Yong, of the Singapore University of Social Sciences, explained that this phenomenon, known as Rayleigh scattering, has to do with certain types of particles that are present during a period of haze.
He told the BBC: “In the smoke haze, the most abundant particles are around 1 micrometre in size, but these particles do not change the colour of the light we see.
“There are also smaller particles, around 0.05 micrometres or less, that don’t make up a lot of the haze but are still somewhat more abundant during a haze period [than a normal non-haze period]… but this is enough to give an extra tendency to scatter red light more in the forward and backward directions than blue light – and that is why would you see more red than blue.”
He said the fact the photos were taken around noon could have caused the sky to appear more red.
He said: ”If the sun is overhead and you look up, [you will be looking] in the line of the sun, so it would appear that more of the sky is red.”