Mumbai, Aug 9 (IANS) Oil spill from the sunken cargo ship, M.V. Rak Carrier has reduced though oil patches have been noticed on Mumbai beaches and further down on Alibag in Raigad district, a top maritime official said here Tuesday.

A close watch is being maintained on the affected site where the ship sank and the rate of oil spill has now reduced considerably, the Directorate-General of Shipping said.

"The rate of flow has reduced to 8 to 10 tonnes per day as compared to 35 to 40 tonnes per day earlier. The continuous trail of the oil leak from the vessel is observed up to 5 to 8 nautical miles as compared to 12 nautical miles earlier," the DGS said in a statement.

However, discoloration has been observed on Alibag Beach in adjacent Raigad, but Indian Coast Guard officials term it as a "usual phenomena" during monsoon.

Besides, tar ball deposits have been seen in the mouth of estuary close to Alibag, while 3-4 silvery patches were sighted near Dadar Beach and Bandra Bandstand sea-face north-west Mumbai.

An official of Maharashtra Pollution Control Board said that no fresh oil deposits have been found at Juhu and Versova Beaches in north-west Mumbai.

Three Coast Guard vessels including oil pollution response vessel Samudra Prahari, and a Dornier aircraft continue to maintain their presence at the site of the sunk ship to monitor the situation 24x7.