The Mysterious Red Rain of Kerala

by Sankalan Baidya
The Mysterious Red Rain of Kerala

The world has been, for times immemorial, tormented by events that don’t really fit into any known scientific explanatory framework. Some of the events just threaten the existing logic and causality we humans are accustomed to. Luckily, some of these paradigm shifting events eventually fit into an existing framework with extensive research while some just remain mysterious and go unexplained. One us event is the mysterious red rain or the blood rain.

The mysterious red rain of Kerala, India baffled the entire world back in 2001. Several explanations were put forward to explain the unusual red stain of the rain. Some were simply rejected and some partially (yes, partially) accepted with several questions remaining unanswered.

Starting July 25, 2001, Kerala experienced an unusual phenomenon. It was monsoon and it rained. While that falls pretty much into the natural cycle as we know but what was really unusual was that this time, the color of the rain was red. This red rain continued till September 23, 2001. Prior to that, red rain in Kerala was reported in 1896. Most recently, the phenomenon was reported in July 2012.

The Boom and the Flash

Just to add to the whole mystery thing, in 2001, a few days before the blood rain phenomenon started, people of Kottayam and Idukki reported as sudden flash of light and a sound in the sky. People say that it was pretty much like a sonic boom. Not only that, people also reported that the trees shredded shrunken and wrinkled burnt leaves. Some even reported sudden formation and disappearance of wells.

The Red Rain Pattern

The blood rain followed a specific pattern. It always rained over a very localized area of no more than a few square kilometers. Some said that the rain was even more localized in certain areas with normal rain pouring down only a few meters from the red rain. At that time, there was no plausible explanation for this localized rain pattern. Even more interesting was that the red rain in specific poured down for no more than 20 minutes.

Suspended Particles in Rain Water

Why was the water red? This question led scientists to test it. They found that about 9 million red particles were present in every millimeter of the blood rain. They further stated that in every one liter of the water from blood rain contain approximately 100 mg of solid. Based on these calculations, the scientists told that for the total amount of red rain that pored down on Kerala, a total of 50,000 kilograms of the red particles came down. Upon further examination, the scientists found that the solid particles they separated from the water were brownish-red in color with 90% of the solid made up of round particles and remain were debris. Further analysis of the solid matter separated from the rain water revealed the presence of green, blue, yellow and gray which go on to explain the unusual black, green and yellow rains that were also reported during the blood rain. Scientists concluded saying that the red rain was because of the red particles.

The Big Question – Where Did the Red Particles Come From?

Initially, CESS (Centre for Earth Science Studies) theorized that the red particles emerged out of an exploding meteor. Remember the sonic boom and the flash of light? Well, that sounded pretty excellent an explanation but somehow, the CESS scientists were not satisfied and conducted further study and within a few days, they discarded their own theory on the following grounds:

1. Had a meteor exploded, the debris from the explosion taking place in the stratosphere would have been carried to different locations by the changes in wind pattern over the two-month period when the red rain was reported. So, if at all it was a meteor explosion, how come the debris from explosion stayed localized instead of being carried away by wind? In essence, if the blood rain was a result of meteor explosion, the red rain would have been reported in different places of the country.

2. Light microscopy of the particles suggested that they were not debris but were actually spores.

Huh? Now, that wasn’t really expected by CESS scientists and hence, they sent a sample of the particles to TBGRI (Tropical Botanical Garden and Research Institute). After of series of microbiological studies, TBGRI along with CESS published a report where it was mentioned that the particles that gave the red color to the rain were actually spores from lichen-forming alga that belonged to the Trentepohlia genus. TBGRI came to this conclusion after comparing those red particles with locally present lichens collected from Changanacherry area.

Fine! Established? Not really, no! There was a problem with this explanation despite having some serious evidences. We will come to this later but before that let us take a look at some of the alternate explanations that tried to find an answer to the mystery of red rain.

Alternative Hypothesis – Blame a Volcano!

Indian Meteorological Department’s senior scientific assistant Mr. K.K. Shashidharan Pillai came up with an amazing explanation. Mr. Pillai noted that Philippines’ Mayon Volcano was erupting at the time when Kerala was experiencing blood rain. So he proposed the theory that volcanic acidic material from Mayon Volcano was carried all the way to Kerala by Equatorial or Eastern jet stream in just about 25 to 36 hours. Well, his theory hinged on the fact that Kerala was at 8°N and Philippines was at 13°N and hence, Equatorial jet stream carrying volcanic material was quite plausible. He also proposed that the acidic nature of the material was the primary cause for burnt leaves.

Sounded authentic but, upon proper examination of the red particles, scientists came to the conclusion that the red particles were not of volcanic origin and hence, Mr. Pillai’s theory was rejected. Sad!

Alternative Hypothesis – Arabian Desert Was the Culprit

Okay, how about Arabian deserts’ dust? This theory was hinged on the observations made by LIDAR just a few days before the red rain. LIDAR readings confirmed atmospheric dust cloud building up over Kerala just a few days before the onset of blood rain. Unfortunately, this theory was also rejected because the analysis of the red particles showed them to be spores and not desert dust.

Alternative Hypothesis – Extraterrestrial Life

This was the boldest of all explanations and this theory in particular stirred up the case of red rain globally. This theory was proposed by Kottayam’s Mahatma Gandhi University’s Santhosh Kumar and Godfrey Louis. Both these physicists proposed that the red cells were extralterrestrial life form released in the atmosphere by the meteor blast. They conducted some tests on the red particles and published their findings which were:

1. Microscopic analysis revealed that the particles were actually living organisms.
2. Those organism grew optimally at a very high temperature of 300 degrees Celsius.
3. The organisms metabolized in a wide range of inorganic and organic materials.

These findings doesn’t necessarily prove that they (microorganisms) were from outer space. Mr. Godfrey Louis however provided an amazing explanation. He said that running DNA staining tests with ethidium bromide did not show DNA in those organisms.

In case you are not aware, every known life form on planet Earth has a DNA. So, if the microorganisms were from Earth, they would have shown DNA during the staining test.

The two physicists actually came up with three papers. The first one was published on arXiv website which was a non-peer reviewed website. The next paper was published in Astrophysics and Space Science in 2008 by the title “The red rain phenomenon of Kerala and its possible extraterrestrial origin” and the final paper was presented in astrobiology conference in 2008. A similar paper was again presented at a conference held in September 2010 in California, USA.

Chandra Wickramasinghe, a Sri Lankan-born British astrobiologist, astronomer and mathematician from University of Buckingham actually supported the findings of Godfrey Louis and Santhosh Kumar.

Why? That’s because Wickramasinghe proposed the panspermia hypothesis by the name cosmic ancestry in which he proposed that life is neither a result of abiogenesis (a process in which life is spontaneously generated from non-living matter like organic compounds) and nor is it supernatural phenomenon. According to the cosmic ancestry theory, life has always existed in entire universe in several higher forms including intelligent life and that life on earth that we see actually descended from there.

Louis’ and Kumar’s finding of microorganisms without DNA seemed to nicely fit into the cosmic ancestry theory and hence, Wickramasinghe supported it.

Counter Argument for Extraterrestrial Life Theory

Now, there were some counter arguments or better put, criticisms to the extraterrestrial life theory. The two physicists did not say anything about how the meteor debris stayed in one place despite changes in wind pattern. Also, Louis said that the cells grew at amazingly high temperature. Well, Louis did not have any biology training and he did say that no standard growth mediums (usually used by microbiologists) were used by him for inducing germination and growth in the red particles (or microorganisms as Louis and Kumar claimed) and hence, the methods used were questionable. Also, the DNA staining method used was usually used for staining bacterial endospores. It is not used for algal spores. The final blow to the theory came for Wickramasinghe who managed to extract DNA from the pores. So, the theory was not correct.

So, was CESS’ and TBGRI’s theory correct?

Possibly! However, there is one question that the scientists from the two organizations did not answer: “How did the spores reach the clouds in the first place?”

Possibly the lichens released their spores but again, the amount of those spores found in the rain water was extraordinarily high. The possibility that the lichens released the spores cannot be ignored but the odds of majority of the lichens releasing their spores simultaneously was slim if not none!

The problem of ‘extraordinary spores dispersal’ is the only major hindrance to the theory put forward by CESS and TBGRI otherwise it is just a very viable explanation.

So, for the time being, we all need to satiate ourselves with the explanation of CESS and TBGRI with a hope that someday they come up with a definitive theory explaining how the spores in such great quantities reached the clouds and put an end to the mystery or red rain or blood rain.

Sources: 1, 2

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Jerry May 21, 2016 - 12:54 am

Perhaps both the volcanic and spore theories are correct. Imagine a volcanic pool with extremophile spores growing in a very hot volcanic environment. The volcano erupts launching the spores into the atmosphere only to rain down on Kerala.

This theory would explain all the details, the bang, the flash, the high temperature propagation of the spores and the large volume of the spores. The Mayon Volcano was erupting at that time, so it’s possible the jet stream carried the spores?

Sankalan Baidya
Sankalan Baidya May 21, 2016 - 1:16 pm

May happen… not sure…

K K Sasidharan Pillai April 5, 2019 - 6:12 pm



I am K.K.Sasidharan Pillai (Rtrd Meteorologist), who has propounded the Volcanic theory of ‘2001 RED RAIN ‘event
I am glad that you are trying to reach the facts to the people. The presence of Lichen spores in red rain is only one of the many questions to be answered. The identity of spores is still in question and more importantly spores cannot initiate other observed phenomenon.
My theory did not get the required attention because every body was bothered about the red colour of the rain only. If my theory is true, the chances of the phenomenon of coloured rain to occur during SW Monsoon period is high, compared to other seasons. As expected, since 2001 , during almost all SW Monsoon season, Kerala received isolated coloured rain.

All are requested to analyse the phenomenon observed in 2001. The primary responsibility is to understand what had happened in 2001. All phenomenon must be closely watched and analysed.

Large quantity of biotic cells can be deposited in to the clouds under certain situations. Spores is only one of the ingredients. I will give an explanation of all points in a few months’ time. I am trying to compile all the related data and it will take time, because of my personal constraints
MY theory is not simply about the eruption of Mayon volcano only . but a detailed meteorological study of the entire troposphere between Philippine to Arabian the time of 2001 event.


Note:Spores should have travelled with volcanic particles….or joined at any point on the route..

Graham June 26, 2019 - 6:13 pm

Around last weekend we had ink Red rain in South Leeds West Yorkshire. It was not a soup it was tranlusant you could see threw it, it was like slightly warted down red ink in a pen. It was in the top of two white plastic bin lids.
Regards Gray.

K K Sasidharan Pillai September 29, 2019 - 12:22 am

Please visit : for detailed reports of red rain event that occurred in Kerala in 2001.
Please go through the pages “RELIVING THE RED RAIN EVENT….”and”THEORY OF RED RAIN”. In the blog more explanation in Malayalam (language of Kerala) and English is given.


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