Worried about the danger posed by sting rays during immersion of Ganesha idols in sea on Wednesday the Brihanmumbai Municipal Corporation will keep an ambulance stationed at Girgaum chowpatty to counter any eventuality. "Our officials visited Girgaum chowpatty yesterday. There is no threat of sting rays now. Sting rays came at the sea-shore (earlier) due to change in climatic patterns," a senior BMC official said.