This paper maps out the structure and relative dynamics of cities of various size classes in India. It aims to address their hierarchical distribution, by employing the rank-size rule, Gibrat's law, and a primacy index. The implications of urban concentrations for GDP, banking system, FDI, civic amenities, and various urban externalities (such as pollution and spatial exclusion) are also examined. It shows that India's urban system, though it follows the rank-size rule, is huge and top-heavy. It follows also Gibrat's law of proportionate growth. Although India's cities collectively account for less than one third of the total population, they command more than three fourths of the country's GDP. Megacities have become congested, clogged, polluted, and also show significant social polarization. There is a gridlock situation for the cities, inhibiting their potential for becoming effective economic and social change sites. The top-heavy character of India's urban system also adversely impacts the balanced regional development of the country.