The coutry's population is likely to reach around 1.5 billion by 2025, according to a United Nations Economic and Social Commission for Asia and the Pacific (ESCAP) projection.ESCAP also estimated that about half the population will live in cities and urban centres by this time, said US Consul-General Henry Jardine at a seminar on "Community-based Disaster Preparedness: the Pandemic threat", here yesterday.Jardine said that as per the other UN projections, India's population may stabilise at around 1.7 billion by 2060."Thus we are likely to face a scenario where nearly a billion people will live in small geographicfal areas. Kolkata already has a density of 24,760 people per square km. So any disaster striking Indian cities will have a massive human impact," Jardine said.India already has at least four cities that have 10 million plus population. In 1991, India had 23 cities with on million or more people. A decade later, the number is 35, he said.Turning to disaster planning, the US Consul-general said a couple of key elements were required in this regard by mobilising the healthcare infrastructure of medical professionals, facilities and laboratories.