The world is increasingly an urban environment. An urban population that is aware of the factors that improve quality of living puts pressure on the environment with respect to dependable utilities, water distribution and sewerage systems, and complicates efforts to maintain the sustainability of the environment and the limited urban sprawl. This pressure extends to green spaces and recreational areas, aesthetics and conservation of heritage sites, and efficient use of real estate and public space within the urban environment. The problem is exacerbated by lack of availability of space needed for developing new functions or relocating and improving existing ones (see Figure 1.1: Effect of urbanization on natural water resources).
In India, population and urbanization have increased manifolds in recent times. The 2011 Census provides a glimpse of these changes—with a population base of more than 1.22 billion, urban housing deficit is touching 23 million. Migration to urban areas has increased phenomenally, as the annual rate of economic growth has hovered around the 8 percent mark. There are 31 cities with more than 10 lakh population.
Out of India’s total geographical area of 329 million hectares (mha), more than 40 mha is flood prone. The average annual flood damage from 1996 to 2005 was Rs 4,745 crore, as compared to the corresponding average of Rs 1,805 crore for the previous 53 years. On an average, every year 75 lakh hectares of land are affected and 1,600 lives are lost in India due to floods. In the past few years, the frequency of major floods has increased to more than one in five years. This can be attributed to many reasons, including a steep increase in population coupled with global warming and, of course, brisk urbanization and increased economic activities in flood plains.