Indian authorities have plugged a fuel leak in a container ship that collided into another cargo vessel off the coast of Mumbai, a senior government official said.
But the principal port of Mumbai near where the collision occurred on Saturday will remain closed until at least Wednesday due to the spill.
The leak was plugged late on Monday after about 500 tonnes of oil had spilled out, Ashok Chavan, the senior chairman of Maharashtra state, of which Mumbai is the capital, told reporters.
The oil slick has spread over an area of nearly five kilometres around the ship, Captain Manohar Nambiar, the defence ministry spokesman, told The Associated Press.
One vessel, which was carrying a cargo of diesel and lubricant oil, tilted dangerously after the collision between the two Panamanian ships five nautical miles from the shore, triggering an oil slick.
Environmental emergency teams have been put on alert to mobilise for a clean-up operation, while fishermen have been told not to venture into the sea until the all-clear has been given.
Broken patches of oil have been cleared around Elephanta Island, a world heritage site and tourist attraction in Mumbai Harbour, the defence ministry said in a statement.
The MSC Chitra was leaving Mumbai when it collided with the MV Khalijia-II, which was manoeuvring into port.
Thirty-three crew members were rescued. Both ships developed cracks following the collision.