It all started with scarlet rain showers last Thursday on some villages in the southern districts of Kottayam and Idukki.

Soon, a similar phenomenon was reported from eight other districts of the state. These areas witnessed spells of green, yellow, brown and black rains.

Almost the entire state, except for two northern districts, have reported these unusual rains over the past week.

Atmospheric dust

Scientists from the Trivandrum-based Centre for Earth Science Studies are now studying the rain waters collected by local people.

The institute's Director, M Baba, said the scientists would not be able to say anything until the analysis was completed. He said it might take up to three weeks to reach a conclusion.

Coloured rains have been reported from some other parts of the world in the past.

Experts said the most likely reason was the presence of dust in the atmosphere which colours the water.

They said yellow rain could be due to sand or the presence of pollen in the air. This was the reason given for coloured rains in Afghanistan a few years ago.