Pollution from Crop Burning Turns Indonesian Skies Red

Skies over an Indonesian province turned red over the weekend, thanks to the widespread forest fires which have plagued huge parts of the country.

One resident in Jambi province, who captured pictures of the sky, said the haze had "hurt her eyes and throat".

Every year, fires in Indonesia create a smoky haze that can end up blanketing the entire South East Asian region.  This year's haze levels have been some of the worst in years.

The haze is caused by open burning in Indonesia and to a lesser extent, parts of Malaysia. The burning usually peaks from July to October during Indonesia's dry season.

Eka Wulandari, from the Mekar Sari village in Jambi province, captured the blood-red skies in a series of photos taken at around midday on Saturday.  The haze conditions had been especially "thick that [day]", she said.

Indonesia meteorological agency BMKG said satellite imagery revealed numerous hot spots and "thick smoke distribution" in the area around the Jambi region.

Associate 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.

"In the smoke haze, the most abundant particles are around 1 micrometer in size, but these particles do not change the color of the light we see," he said.

"There are also smaller particles, around 0.05 micrometers or less, that are somewhat more abundant during a haze period, which scatter red light frequencies more in the forward and backward directions than blue light - and that is why would you see more red than blue."

The blame for the haze lies with big corporations and small-scale farmers, which take advantage of the dry conditions to clear vegetation for palm oil, pulp and paper plantations using the slash-and-burn method.

This slash-and-burn technique employed by many in the region is arguably the easiest way for farmers to clear their land and helps them get rid of any disease that may have affected their crops.

However, these 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.