Bhopal gas tragedy victims attend a protest organised by non-governmental organisation (NGO) 'Bhopal Group for Information and Action' in New Delhi November 8, 2010. Hundreds of victims on Monday demanded that U.S. President Barack Obama ensure U.S. chemical firm Union Carbide and its parent company Dow Chemical's accountability for the industrial catastrophe that took place in Bhopal in 1984. More than 3,500 people died in the world's worst industrial disaster after a poisonous gas spewed out of a factory in 1984. REUTERS/Adnan Abidi (INDIA - Tags: CIVIL UNREST POLITICS ENVIRONMENT BUSINESS)