New Delhi, July 12 -- After the collapse of three buildings near an underground metro construction site in Sadar Bazar's Mithaipul area, the Delhi Metro on Friday issued a list of precautionary measures it follows during tunnelling operations to ensure public safety. The move comes in the wake of a tragic incident in which one person died during debris clearance following the collapse. The Delhi Metro said the measures undertaken during tunnelling include a pre construction building survey and condition mapping. The existing condition of buildings, including any visible cracks or damages, is recorded with photographic and video evidence in the presence of occupants and jointly signed off by them, it added. "In cases where required, strength...