People wave towards a helicopter carrying Hindu nationalist Narendra Modi, the prime ministerial candidate for India's main opposition Bharatiya Janata Party (BJP), after an election campaign rally at Mathura in the northern Indian state of Uttar Pradesh April 21, 2014. Around 815 million people have registered to vote in the world's biggest election - a number exceeding the population of Europe and a world record - and results of the mammoth exercise, which concludes on May 12, are due on May 16. REUTERS/K. K. Arora (INDIA - Tags: POLITICS ELECTIONS TPX IMAGES OF THE DAY)