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.
A meteorology expert told the BBC the unusual sky was caused by a phenomenon known as Rayleigh scattering.
PSI in Pekanbaru, Indonesia surges to 700
The PSI reading in Pekanbaru, the capital city of Riau in Indonesia, surged to 700 on Sunday, Sep. 22, at about 10pm, according to The Straits Times.
According to Indonesia’s national disaster agency, some 328,724 hectares of land had already been burnt in the first eight months of the year.
Haze turns Indonesia sky red
According to the Meteorology, Climatology, and Geophysics Agency (BMKG), the red sky is caused by something called “Mie scattering”. This is when the diameters of air particles match the wavelengths of light. The particles then block out certain colours of light.
In Indonesia’s case, the air was so filled with tiny particles, about 0.7 micrometres in diameter, that they blocked out nearly all the light from the sun. As a result, only the red light from the forest fires could reach the town.
The smog, dust and airborne particles from the ongoing blaze in the region basically filter out shorter wavelengths of light (blues and greens) while dispersing longer wavelengths (red, orange, yellow), resulting in the Martian-esque scenery that you can see with the naked eye.