While authorities launched a probe into the collision and summoned the captains of both ships for questioning, the Central Pollution Control Board(CPCB) sought to calm fears of serious environmental damage and said that the quantity of oil that had spilled was not large enough to cause major harm.

But the incident hurt movement of sea traffic, with barely a handful of small ships managing to reach or leave Mumbai Port Trust and Jawaharlal Nehru Port Trust on Monday as large containers from MSC Chitra that fell into the sea after the collision floating around dangerously or sitting on the shallow sea bed and posing a danger to large vessels. Fishing in the area has also been stopped.

Minor oil slicks also reached the shores of Elephanta and Butcher Islands, two islands located off Mumbai’s eastern seaboard. But Coast Guard officials who sighted these patches during aerial surveillance along with patches at BARC, Sewri and off Middle Ground, cleared them by spraying chemical dispersants. Otherwise, officials said, there was no cause for alarm as district collectors of Thane, Navi Mumbai and Raigad had confirmed that there was no sighting of oil on their coast.

But officials said water samples from coastal areas would continue to be tested over the coming days as Chief Minister Ashok Chavan had directed all tehsildars in coastal areas to collect and test samples from sea to check if the spill was traveling toward them, Environment Minister Suresh Shetty told reporters. The tests will be conducted along the coastline from Raj Bhawan in Mumbai to Mandwa, said Shetty, who accompanied Chavan and officials on an aerial survey of the spill. He added that in case the oil slick reached the coastline, an action plan was ready as per Coast Guard protocol, and said the Coast Guard had been asked to give a list of equipment the government would procure.

Officials said cargo ship MSC Chitra, which collided with MV Khalijia III, had tilted 70 per cent, sending about 300 of its 1,219 containers into the sea. While some of them had sunk, others floating were towed ashore. Nine containers found floating around Uran today were found to contain milk powder, while a few others which surfaced at Cuffe Parade in south Mumbaiand surrounding areas had shampoo and imported biscuits.

Although the Directorate-General of Shipping said that 31 containers on the ship were carrying hazardous cargo such as chemicals, these containers were found to be secure. A Coast Guard helicopter which conducted a survey spotted 24 of these containers in Bay 2 of the front deck, while another four were spotted secure at Bay 3 and the rest at Bay 4. it said the vessel had about 1,200 tonnes of fuel oil in the ruptured tanks on the port side and remaining in her starboard side which is out of the water. a total 2,700 tonnes of fuel oil and 300 tonnes of diesel oil is on board, it added.

Principal Secretary (Relief and Rehabilitation) J S Saharia said that some containers from MSC Chitra had fallen into the Mumbai Port Trust approach channel. “This may affect the navigation of ships,” he said, adding that measures were being taken to remove the containers which would be shifted to the Jawaharlal Nehru Port Trust.

In Delhi, CPCB chairman Dr S P Gautam told The Indian Express that the full implication of the oil spill was yet to be assessed but considering the amount of oil on the ship, the situation looked manageable and the damage was likely to be limited. “We do not know how much oil will finally go into the water. Some of the containers on the ship are sealed. We understand that not all of the oil on the ship will go down in water. The quantities are not very large and do not pose a major environmental disaster,” Gautam said. Officials said that Prime Minister Manmohan Singh has asked for a preliminary report while Environment Minister Jairam Ramesh will make a statement in Parliament on Tuesday.

Gautam, however, said that quick response from the Coast Guard had helped in containing the damage to manageable levels. He said the Coast Guard had started spraying anti-oil chemicals that would break down the oil. Besides, the sea near the port was quite rough, aiding quicker dilution of oil in the water. “I do not think there would be massive environmental impact. We are keeping a close watch on the situation. By tomorrow evening, hopefully, we will have a correct assessment of the quantity of the spillage as well as the likely damage,” Gautam said.

The incident echoed in Parliament today with Congress MP Shantaram Laxman Naik and BJP's Rajiv Pratap Rudy demanding quick action from the government to contain the damage. Environment minister Jairam Ramesh, while offering to make a comprehensive statement on Tuesday, said the Maharashtra State Pollution Control Board had already initiated legal action against the owners of the ships, both of which are registered in foreign countries.