A volcano on the Indonesian tourist island of Bali sent plumes of grey smoke and steam thousands of metres into the air for the third day in a week on Sunday. Mount Agung spewed smoke and ash as high as 4,000 metres this morning.<br/><br/> A spokesman for Bali's airport said the volcanic activity caused at least 28 departing or arriving flights to be delayed or cancelled, which have left thousands of tourists stranded. Indonesia's volcanology centre has put out a red alert warning airlines of a possible eruption, with a likely significant emission of ash into the atmosphere. Mount Agung last erupted in 1963, killing nearly 1,600 people.