Continuing the history that I began here: When India became independent of Britain in 1947, it existed for a brief period as the Dominion of India. That left it in a position somewhat similar to that of Canada, being self-governing, but with the British monarch as head of state.
India then became a republic, when it adopted a new constitution in 1950.
The head of state is a president, who is elected by members of the federal parliament and the state legislatures. The current president is Pratibha Patil, who was elected in 2007, and is the first woman to hold that office. The limited political role of the Indian president is similar that of the British monarch.
The head of government is a prime minister, who is selected in a manner similar to that of the British prime minister. Since 2004, Manmohan Singh has held that office.
So far, I've pointed out similarities between the Indian system and that of its former colonial ruler, Britain. However, India takes a different approach toward regional government, the implications of which include the following:
India has a federal system, i.e., it consists of 28 individual states, whose governments are sovereign within the scope of responsibility left to them by the federal constitution. While, in practice, the states' autonomy is more limited than that in other federal systems, such as that of the U.S., it is, in theory at least, a less centralized structure than that of the U.K., even after devolution of power to Scotland, Wales and Northern Ireland.
The governments of those states elect most of the members of the upper house of the Indian parliament, which is called the Rajya Sabha, the Council of States. That contrasts with the British House of Lords, where succession was traditionally hereditary, and now is mostly done through appointment by party leaders.
In that regard, the Indian system is more similar to that of Germany, where the states elect members of the Bundesrat, their federal upper house. It is also somewhat similar to that of the U.S., where the states, as such, are represented in the Senate. There is an even greater similarity to the original U.S. Constitution, under which senators were elected by the state legislatures.
Elections to the Indian lower house, the Lok Sabha, House of the People, are similar to those for the U.K. House of Commons. One member is elected from each parliamentary constituency. There is, under normal conditions, a maximum five-year interval between general elections. The next one is to be held by May of this year. Another similarity to the U.K. is that the Lok Sabha has more of the legislative power than does the upper house.
Next: history of elections and parties under that political structure.