Goa's popular beaches turned black on Monday evening due to a suspected oil spill off the coast of Panaji.
Beaches like Calangute, Siquerim, Candolim in north Goa and Colva, Betalbhatim and Sernabhatim in the south were covered with black tar balls, eyewitnesses said.
"Entire south Goa beaches are covered with black oil which has been washed ashore," a source said.
Tourism Department Director Swapnil Naik said they have sent teams to take stock of the situation. He said there was no cause for panic.
"There is nothing to be alarmed. Usually such tar balls surface on the beaches during monsoons," Naik said.
Collision of two merchant ships off the Mumbai coast on August 7 had caused a massive oil slick in the metropolis' shores and some surrounding areas.