Indians are voting on the biggest day of the country's general elections, with nearly 200 million people eligible to cast their ballots in 12 states.

Voters streamed into polling stations across the vast country, from the western desert state of Rajasthan to the tea-growing Himalayan areas in the east; and from the troubled state of Kashmir in the north to the technology hub of Bangalore in the south.

Nationwide voting began April 7 and runs through to May 12, with results expected to be announced four days later.