KAIRANA/CHENNAI, India (Reuters) -India began voting on Friday in the world's largest election as Prime Minister Narendra Modi seeks a historic third term in office on the back of growth, welfare, his personal popularity and Hindu nationalism.

The vote pits Modi's Bharatiya Janata Party (BJP) against an alliance of two dozen opposition parties which is challenging him with promises of increased affirmative action, more handouts and what they say is the need to save democratic institutions from Modi's dictatorial rule.