It was as though a biblical plague struck parts of Sri Lanka last week when showers of blood-red coloured rain fell from the sky. There seemed to be no obvious cause for such a bizarre spectacle — there were no red sand storms, clouds of pollen or pollution from factories that might cause the red rain. Eventually, a study revealed the spores of a tiny one-celled red alga, Trachelomonas, in samples of the rainwater. Usually found in the soil, the algae is known to have caused red rain and even snow in other parts of the world.
The state of Kerala,