Indian civilization has been one of the most pervasive and important influences on human history. To the east, throughout the area we know as Confucian civilization, Indian-derived Buddhism has been an omnipresent influence; in Japan, at the point of Confucian civilization most distant from India, when a family member dies, Buddhist rites are the norm. To the west, and indeed throughout the world, Christianity exhibits a multifaceted Indian legacy. The early Christian church was structured on Indian models. Every Catholic who prays the rosary is following an Indian tradition.
Like China, India has the advantages and disadvantages of a huge, complex society. The principal disadvantage is that these societies are difficult to manage, and both countries have paid a heavy price in parts of the 20th century for those difficulties. The principal advantage is that they are both cosmopolitan societies, comfortable with different kinds of people, benefiting economically from diasporas that have spread to every populated part of the world. In both cases, the diasporas have until recently fared better than the population at home who were burdened by huge socialist bureaucracies; as a result, the diasporas have enormous ability to bring back wealth, technology, and market connections that are relatively lacking at home.
India's and China's diversities are both vast, but they differ in kind. China assimilates diverse groups into a common Confucian culture despite a diversity of dialects, physical types, and cultural origins; although they conquered China, the Manchus and most of the Mongols became part of the melting pot. India accumulates diverse groups, which identify themselves as Indian but retain highly distinctive cultures to a far greater extent.