India is the most populous democracy in the world. For most of its democratic history, it has been led by the Indian Congress Party. The Constitution of India is the longest constitution of any other nation in the world. It defines India as a sovereign, socialist, secular and democratic republic. India operates under a Westminister-style parliamentary system. The President of India is the head of state. While he holds substantial reserve powers, the Presidential role is largely ceremonial.
The Constitution authorises the Parliament of India to oversee the operation of the government. The parliament in turn consists of two houses, The Rajya Sabha (Council of States) and the Lok Sabha (House of the People). The Council of Ministers is held responsible to the Lok Sabha. India is divided into 28 states and seven union territories. Each state has its own elected government while Union Territories are governed by an administrator appointed by the central government. The states' chief minister is the official head of his state and is responsible to the legislatures in the same way the prime minister is responsible to parliament.