Like China, India was also blessed with a strategic geographical position which allowed it to exert influence in its region. If China is the Middle Kingdom in the great Asian land mass, India is the center of the great Indian Ocean basin. While China was able to traverse land and sea routes for trade and cultural exchange, India had the coastlines looking over the whole Indian Ocean for it to sail to Asia, Africa and Europe. The Byzantine also possessed this pivotal position as the crossroads of East-West trade. All three countries optimized this advantage for economic gains.
Both India and China have large land masses and rich natural resources which allowed them to support the largest populations on earth. They vary though in socio-political structure as China was able to unify its populace under dynasties that came one after the other. On the other hand, India was never unified under one powerful state. There were always two to three regional kingdoms in power at the same time. This disunity did not allow a national campaign of conquest unlike what the Tang dynasty was able to accomplish.
If Byzantine Empire had the theme as the unit of government by which all military and economic activities surround, India had religion as the organizing factor, wherein temples are the central points by which agricultural activity thrives. Temple officials also act as administrators, bankers and financiers to the farmers. Temples grew prosperous but they supported the economic well-being of their constituents. They also ensure the peace by managing the tax payments to the political authorities.
India's contact with Islam was mostly through trade and conversions were many such that there was no appeal for jihad compared to the violent invasions inflicted on the Byzantine empire. Eventully one quarter of the population became Muslims which presaged the splitting of Hindu India and Muslim Pakistan in the 20th century.