Where and when did the ''red rain'' incident take place?

Kerala red rain phenomenon was a blood rain event that occurred in Wayanad district region of Malabar on Monday, 15 July 1957 and the colour subsequently turned yellow. Also on 25 July to 23 September 2001, when heavy downpours of red-coloured rain fell sporadically on the southern Indian state of Kerala, staining clothes pink. Yellow, green and black rain was also reported in Kerala in 1896 and several times since, most recently in June 2012.

It was caused due to chemical imbalances in environment. Such as some water samples were taken to the Centre for Earth Science Studies (CESS) in India, where they separated the suspended particles by filtration. The pH of the water was found to be around 7 (neutral). The electrical conductivity of the rainwater showed the absence of any dissolved salts. Sediment (red particles plus debris) was collected and analysed by the CESS using a combination of ion-coupled plasma mass spectrometry, atomic absorption spectrometry and wet chemical methods. The CESS analysis also showed significant amounts of heavy metals, including nickel (43 ppm), manganese (59 ppm), titanium (321 ppm), chromium (67ppm) and copper (55 ppm).The red cells found in the red rain in Kerala, India are now considered as a possible case of extraterrestrial life form. These cells can undergo rapid replication even at an extreme high temperature of 300 °C. The molecular composition of these cells is yet to be identified.