India's Supreme Court has banned the Exxon Valdez from entering India, saying the ship involved in one of the worst U.S. oil spills will not be allowed in for dismantling until it has been decontaminated.

The ship, now known as the "Oriental Nicety," entered Indian waters last week and was headed for the western Indian state of Gujarat, when the Supreme Court gave its order, environmental activist Gopal Krishna said Wednesday.

The ship was bought recently by the Hong Kong-based subsidiary of an Indian shipbreaking firm and was being taken to the coastal town of Alang, the hub of India's shipbreaking industry, for dismantling.

After the court's order, Gujarat maritime authorities and the state's pollution control authorities withdrew the permission they had granted to the company to anchor the ship near the Alang beach.

Krishna, the environmental activist, had filed an application asking the Supreme Court to give directions to the Indian government and the shipping ministry on the purchase of the ship and its entry into Indian waters. The court has issued notices to the government and the ministry asking for information on steps it intends to take regarding the ship.

The Gujarat company contracted to dismantle the ship plans to appeal the court order.

"We will abide with the Supreme Court order. We are studying the order, and will appeal," said Harshadbhai Padia, a partner in the company.

On March 24, 1989, millions of gallons of crude oil spewed into Alaska's ecologically sensitive Prince William Sound when the Exxon Valdez dashed against rocks, coating the shoreline with petroleum sludge and killing nearly 40,000 birds. The spill caused incalculable environmental damage and demolished the area's fishing industry.

Texas-based Exxon Mobil Corp., spent $900 million in restitution in a 1991 settlement and is battling more litigation from the spill.

The tanker moved on, with five name changes since the spill and ownership changing repeatedly, apparently to keep the ship in use while distancing it from the disaster.

The ship is 26 years old, not significantly aged for tankers, but it was considerably damaged in its lifetime. It was split open by rocks in the Alaska spill and was damaged in a collision in the South China Sea in 2010.

The Indian court cited the Basel convention, an international treaty that calls for decontamination in a ship's country of export. Mercury, arsenic, asbestos and residual oil can contaminate ship hulls and holds.

India has one of the world's largest industries for breaking down old ships and oil tankers centered around Alang, and workers in the coastal town are expected to process the ship to salvage scraps of metal and parts that retain value.

However, environment activists say that shipbreaking companies do not follow any precautions while breaking and handling end-of-life ships, exposing workers and the environment to toxic materials.