India holds a parliamentary election in April and May 2014. It is expected that the various parties, candidates, and other participants will spend $5,000,000,000. This will be the second most expensive election campaign in world history, topped only by the U.S. 2012 election. See this story.
Indian polls are only open one day, but each state votes on a different day. The election dates for the 2014 election run from April 7 to May 12. India will fill all 543 seats in Parliament. This year India appears to have a multi-party system. See this wikipedia article on the election.