A boy holds a poster of Rahul Gandhi, India's ruling Congress party's vice president and son of Congress chief Sonia Gandhi, after an election campaign rally in Kolkata on May 8. Around 815 million people have registered to vote in the world's biggest election - a number exceeding the population of Europe - and results of the mammoth exercise, which concludes on May 12, are due on May 16. If the party wins the election, Rahul Gandhi is expected to become the prime minister. -Reuters/Rupak De Chowdhuri