Varahamihra the unparallel genius in mundane astrology gives lot of emphasis on nimitta in his classical book. if you see lot of techniques and slokas in his book, they are based on the plain observation and also on nimitas . there are several reason to stress on nimita . First of all one does not get the correct birth time of nations and individuals . one can easily use the predictions based on these celestial events.
 
Let us see what happened in the state of Tamilnadu. Mars came close to the earth. Mars is bhumi karaka it can came closer to earth . I had written in my website there will be mass death in the states of Tamilnadu , Andhra ,kerela and Karnataka.
 
Secondly there was mock sun . two sun was seen in the district of cuddalore and also black halo was seen around the sun. when double sun was seen in china, Yangtze river broke it banks.
 
 
Thirdly jayalaitha took the oath in rishbha lagna. There was exchange between the 8th and 6th lord . 8th lord is Jupiter in sixth house and 6th lord Venus in the 8th house. There fore there will be loss of lives and property in state of Tamil nadu. It is also the bhukthi of Venus. It is also the bhukthi of rahu which is with Saturn.