Desilting work underway at Puzhuthivakkam lake in the city Rapid urban expansion, shrinking vegetation and waterbodies, drainage gaps, and low-lying terrain contribute to flood risk, according to a University of Madras study. The city’s flood-risk hotspots include Velachery, Pallavaram, Chromepet and surrounding southern localities, parts of western Chennai, Koyambedu, Villivakkam and areas around Tondiarpet.The study…