Tamil Nadu Chief minister Mr M.Karunanidhi has stressed the need for incorporating caste based details in the ongoing census without postponing it to the biometric stage.In a letter to the Prime Minister, Mr karunanidhi said a few changes in the existing census format by experts will be sufficient to achieve the object of caste based census.The Chief minister said he firmly believed that caste based census will go a long way in ensuring that the fruits of the various developmental schemes implemented by the central and state government will percolate down to the lower strata of the society.