08/08/2011 02:49 pm ET | Updated Oct 08, 2011

Mumbai Oil Spill Being Cleaned Up By Indian Coast Guard (PHOTOS)

NEW DELHI (AP) — The Indian coast guard is still working to clean up spilled oil from a merchant ship that sank off Mumbai four days ago.

The defense ministry said in a statement Monday that an aerial survey showed the oil slick around the MV RAK had decreased and oil was now spilling at about one ton per hour.

The vessel had been transporting coal from Indonesia to the western Indian state of Gujarat and was estimated to be carrying 325 tons of fuel oil and 56 tons of diesel.

A separate government statement suggested the oil slick off Mumbai's coast was caused by something other than the sinking of the MV RAK. The statement did not elaborate.

Another merchant vessel has been stranded off Mumbai's coast since July 31.

View photos of the oil spill below:

India Oil Spill