PANAJI, India (AP) — Wave after wave of tar balls floated ashore on the renowned Goa beaches after a ship dumped tons of waste oil off India's western coast, officials said.

Semisolid lumps of oil formed layers up to six inches deep on beaches in the popular tourist destination.

Scores of civic workers used brooms to collect and clear the oily debris, but still more tar balls were washing ashore about three days after officials believe a ship dumped burned oil at sea.

Indian navy and coast guard vessels were trying to trace the ship, said Aleixo Sequeira, the state's environment minister.

He declined to say what action would be taken when the vessel is found.

Ships regularly clean their fuel tanks and discharge the waste oil at sea, but this case involved careless dumping that exceeded all proportions, say scientists at India's National Institute of Oceanography, located in Goa.

"Crude oil mixes with water to form an emulsion that looks like chocolate pudding. Winds and waves continue to stretch and tear the oil patches into smaller pieces, or tar balls," said S. R. Shetye, who heads the institute.

Popular beaches such as Colva, Candolim and Calangute were badly hit.

The beaches are not closed, but few visitors are there since tourism season begins in October.

Goa's tourism industry is worried that news of the pollution could put off visitors to one of the most sought after and cheap beach destinations in India.

Nearly 2.5 million tourists visit annually, including half a million foreigners, mostly from the UK, Israel and Russia.

"This should not have happened. It will not be good for tourism in Goa," said Gaurish Dhond, president of the Travel and Tourism Association of Goa.

The tourist season in Goa lasts until March.