Tamil Nadu police on Friday registered cases against the management of two tankers that collided last week leading to a massive oil spill along the coast, that has affected marine life in the area.

On January 28, MT Dawn Kanchipuram, carrying petroleum oil lubricants (POL), and MT BW Maple, loaded with LPG, collided off Kamarajar Port in Tamil Nadu.

Several tonnes of crude from MT Dawn spilled into the sea. The oil has spread over a 30 km stretch along the coast, from Ennore where Kamarajar port situated.

Based on a report filed by the Kamarajar port authorities, the Minjur police station in north Chennai filed cases and asked the captains of both oil tankers to submit their reports immediately.

Cases were registered under six sections, including on charges of polluting the sea waters.

A senior official from Kamarajar port said that officials of the Directorate General of Shipping were conducting a detailed enquiry to ascertain the reason for the accident.

ICG East region Inspector General Rajan Bargotra said the oil spill was around 34,000 square metres in area. He said the oil patches near the shore have to be removed manually.

Meanwhile, the Madras High Court has refused to detain the two oil tankers.

When a PIL came up for hearing, Chief Justice S.K. Kaul and Justice M. Sundar said it was up to the Central and the state governments to take necessary action in the matter.

The Coast Guard said it had recovered 40 tonnes of oil and 27 tonnes of oil and water mix and were using super-sucker pumps to clean the oil and NGOs were also involved in the clean-up operation.

On January 31, the Coast Guard said in a statement: "It is estimated that more than 20 tonnes of oil has spilt from MT Dawn Kanchipuram as against the initial report of two-three tonnes."

Many turtles and fishes have died and washed ashore due to the oil pollution, environmentalists have said.