Mumbai, India’s premier city, and the nation’s financial and industrial capital is going through a crisis. The population of the city is growing at 4.5 percent per annum. Predictably, most growth is by migration from poor, rural areas. In 1960, squatters were estimated to be less than 4 lakhs in a population of 4.5 million. By 1980, their number rose to 4.5 million in a population of 9 million. Greater Mumbai is now the sixth largest mega city in the world, with 16.4 million population. Nearly half the people live in slums.Now a debate is raging on about large scale migration from the poorer areas of Bihar, UP, MP, AP, TN and Maharashtra itself. Several influential people and political parties are seriously suggesting eviction of squatters from unauthorised slums violative of zoning  laws. Several cut off dates are suggested. About 8 lakh people established residence in such unauthorized areas since 1995. Obviously eviction on such a large scale is going to present a megascale human problem. Rehabilitation of slum dwellers elsewhere is both costly and impractical. People live close to their means of livelihood and slums come up because of economic forces. And there are bound to be political compulsions at work. In a democracy, numbers speak. No party can ignore the urban poor.  Greater Mumbai now has 37 Assembly Constituencies out of Maharashtra’s 288. With delimitation based on 2001 census, this number may well exceed 50. There are some voices supporting ban on entry of migrants to Mumbai unless they have a place to live. But constitutionally such a practice is impermissible. Every citizen has a right of movement, residence and employment all over the country. Only Communist dictatorships succeeded in preventing people from migrating to big cities.Clearly, this is a problem with no obvious solution. And yet, we cannot wish away the problem. In many ways, the problems of Mumbai are not unique. Delhi, with a population of 11.7 million, has over 3 million slum dwellers in 1500 shanty towns. All other major cities face similar problems. And yet India is rapidly urbanizing. Already, with over 310 million, India has the second largest urban population in the world. India Development Report 2002 says that over two-thirds of the urban population lives in the 34 urban agglomerations with population exceeding one million.This urbanization is a global trend. The level of urbanization in the world increased from 30% in 1950 to 51% in 1990. The most rapid urbanization is witnessed in developing countries, where the urban population ratios doubled. This, with a high population growth has exerted enormous pressure on cities.Economists say that with rapid economic growth, spatial concentration of development, and consequent growth of cities is inevitable. Burgess and Venables  argue that access to labour, capital and markets, basic infrastructure, skills, technical know-how, networks and market linkages make cities efficient in modern production. As a result the poor migrate from under-developed regions in search of livelihoods. That is why the number of cities in the world with a population of more than 1 million went up from 115 in 1960 to 416 in 2000; for cities of more than 4 million the increase was from 18 to 53; and for more than 12 million (megacities) from 1 to 11 (Henderson 2003). Dominance of megacities is particularly common in poor countries. The problem is exacerbated in India by enormous regional economic disparities. Maharashtra, India’s richest large state, enjoys a percapita income 3.5 times higher than that of our poorest state, Bihar. And this disparity is growing, as poorer areas are stagnating. Mumbai therefore is a magnet to many abjectly poor rural Indians.  But India as a whole is a poor country, and most regions are densely populated. Migration therefore leads  to growth of urban poverty and serious divisions in  society. Sons of the soil policies and regional chauvinism are manifestations of these problems. In a fundamental sense, Mumbai’s fate is inextricably linked to Bihar.What can be done to address the crisis? First, we need to constantly reinvent our cities, and allow growth with dispersion, with adequate space for the poor. Slums are a result of poor planning, lack of anticipation and passive management. People do not court misery. Desperation and growing job opportunities force them to live in slums close to work. Second, public housing and humane rehabilitation of the poor in residential zones must be a high priority. The problems of big cities are a national problem, and must be addressed nationally. Third, massive investments are needed in infrastructure to promote growth in poor regions. If Bihar dies, India cannot survive. What we need is in situ  urbanization, as seen in Tamil Nadu; not large-scale migration to distant big cities. But money is not enough. Lawlessness, corruption and intense casteism and oppression cannot promote growth. Strong political will to establish rule of law and sensible governance reforms are critical to promote prosperity, give hope to millions and create local counter-magnets.