* More than 800 million people registered to vote
* Voting to take place over five weeks, BJP leads polls
* Voters angry over graft, look to BJP for jobs, polls say
* Ruling party says BJP cares only about Hindu majority
By Shyamantha Asokan
LEZAI, India, April 5 (Reuters) - The biggest election the world has ever seen begins on Monday in a remote backwater of tea gardens and rice paddies, with India looking increasingly likely to embrace a coalition led by a Hindu nationalist to jumpstart a flagging economy.
India's 815 million voters are set to inflict a resounding defeat on the ruling Congress party, led by the Nehru-Gandhi dynasty, surveys show, after the longest economic slowdown since the 1980s put the brakes on development and job creation in a country where half of the population is under 25 years old.
Despite misgivings among many Indians about his handling of religious riots in 2002, Narendra Modi, the prime ministerial candidate of the main opposition Bharatiya Janata Party (BJP), has dominated a lengthy, frenetic campaign where parliamentary candidates range from a tech billionaire to a magician.
Voting will take place in nine stages over five weeks, kicking off in two small north-eastern states close to Myanmar, then spreading to the frozen Himalayan plateaus, western deserts and the tropical south before ending on May 12 in India's densely populated northern plains. Results are due on May 16.
Assam, one of the lush but under-developed states where the election begins, is a rare bastion of support for Congress. But even here some villagers are impatient for change, saying they want highways to replace potholed country lanes so they can sell their crops and fish to markets across India.
"We have had some development but the pace is not fast enough. We need the next step ahead," said Manaspratim Buragohain in the village of Lezai, on the banks of a tributary of the huge Brahmaputra river and surrounded by paddy fields.
"Our businesses stay small because we need better roads and bridges," said Buragohain, a school teacher.
"VERY SAVVY" CAMPAIGN
Modi, three-times chief minister of the western state of Gujarat, has run a high-octane campaign, with many rallies even in the south and north-east where the BJP is traditionally weak.
Across India, Modi - who will run for the holy Hindu city of Varanasi - has vowed to revive a $1 trillion infrastructure programme, create jobs and help an ambitious, growing middle class whose economic success has sputtered in recent years.
"The Modi message has been very savvy," said Milan Vaishnav of the Carnegie Endowment for International Peace.
"He's pitching at the Indian middle class - people who are on $4-10 a day, people who were until recently poor but now can afford consumer goods. Even the poorest people, those below that group, want some of that," said Vaishnav, an India expert.
While Modi has cut red tape and overseen a period of high growth in Gujarat, details of his policy plans, or "Modinomics", on the national scale remain sketchy. The BJP is due to release its delayed manifesto after voting starts on Monday.
The BJP and its allies are forecast to win the biggest chunk of the 543 parliamentary seats up for grabs but fall up to 38 seats short of a majority, according to an opinion poll released this week by CSDS, a respected Indian polling group.
The debate in New Delhi is focused on whether Modi can secure a stable-enough coalition to push through his agenda.
However, Indian elections are notoriously hard to call. Opinion polls in 2004 incorrectly predicted victory for a BJP-led alliance campaigning on its economic record. The centre-left Congress instead swept to power to expand welfare schemes.
Congress, now dogged by public anger over the economic slowdown and corruption after a decade in power, is forecast to get around half of the BJP's tally. The Nehru-Gandhi dynasty has in recent months lost much of its traditional ability to rouse voters, with many unimpressed by its scion Rahul Gandhi.
India's next prime minister will face a tough job reviving an economy plagued by high inflation and a wide fiscal deficit. Other challenges include defining India's role in a tense neighbourhood marked by border disputes with Pakistan and China.
The three countries are jockeying for position in Afghanistan, which held elections on Saturday, as Western troops withdraw from the war-battered nation.
Critics say Modi represents only India's Hindu majority and failed to stop or even allowed communal riots in 2002 in Gujarat, in which at least 1,000 people died, most of them Muslims. He has always denied the accusations and a Supreme Court inquiry found no evidence to prosecute him.
"India's uniqueness is its unity amongst diversity," Paban Singh Ghatowar, the Congress candidate for the constituency that contains Lezai village and a junior cabinet minister, told Reuters. " represents one line of thinking. He does not represent the diversity of India." (Additional reporting by Biswajyoti Das; Editing by Frank Jack Daniel and Gareth Jones)