After blue, its now black. The colour of the water of river Dikhow has turned blackish these days. The incident of change of water colour of the river has created a curiosity among the conscious section. The Pollution Control Board in the district had undertaken steps towards testing the river water after collecting samples on May 11 and 12 from Amgurighat and Metekaghat of Sivasagar district and sent to regional research laboratory in Guwahati. But according to sources, the reason was not identified. Keeping in view the seriousness of the matter and possible environmental issue, the district administration of Sivasagar has taken initiative towards testing the river water with the help of scientists and experts engaged at the regional research centre in Guwahati and for the success of the test it has already collected needed datas and samples after visiting the origin of the river at the Assam–Nagaland border and also collected samples from Bihubor and Santak where there are abundant of open coal mines and ores of stones.