Black color water with smell from borewell

Hi,

My house location is Madurai.

From last three days, we are facing the borewell water problem, the water is black in color with smell. As our borewell is 400 ft, it is not possible that the drainage water will get mixed with the borewell water. 

Earlier water was good with no problem. I am confused on how to find a solution to this problem and whom to contact. Water samples are attached, kindly view and suggest .

Regards,

Janakiraman R