What problems caused by diversity does Indria Gandhi refer to in this quotation: India has not ever been any easy country to understand. Perhaps it is too deep, contradictory, and diverse.
In her observation, Indira Gandhi, the late prime minister of India, was acknowledging the social, cultural, religious, and political complexity of the nation she governed prior to her 1984 assassination. India is a large and ancient society riven with deep fissures separating ethnicities and religions. The British withdrawal from its most prized colony led to an enormously bloody civil war between the nation's Muslims and Hindus, with the former breaking away to form current day Pakistan and Bangladesh (originally, East Pakistan until it broke away from Islamabad and formed its own independent nation). Tensions, occasionally breaking out into open violence, between Hindus and Muslims remain a defining characteristic of India, as do secessionist sentiments on the part of the nation's Sikh community. In addition, since 2004, a violent Marxist insurgency called "the Naxalites" has inflicted considerable bloodshed of its own on the desperately poor Indians who reside in central India.
In addition to the divisions mentioned above, India's is a rigid caste system that further defines the nation's society. Those born to poor families are, under this system, condemned to remain among the bottom rungs of India's socioeconomic ladder, while those born to wealthy families enjoy all of the privileges such status automatically confers upon those fortunate to belong to the upper classes. Finally, India's dominant religion, Hinduism, is enormously complicated and enormously influential in the day-to-day lives of its population of over one billion people. This polytheistic religion permeates the lives of much of the nation's population, often at the political expense of the hundreds of millions of Indians who identify themselves as Muslim.
In short, India is, as Prime Minister Gandhi noted, hopelessly complex, and the challenge of governing it remains as formidable as ever.