Members in the Rajya Sabha today observed silence as a mark of respect to the memory of those who lost their lives in the Bhopal Gas tragedy, which took place on this day thirty one years ago. Making a reference in the House, Chairman Mohammed Hamid Ansari said the scars of the man-made tragedy of unparalleled magnitude continue to haunt in the form of incapacitated people, people suffering from various ailments due to the contamination and children born with physical and mental disabilities.