By Sruthi Gottipati and Frank Jack Daniel
NEW DELHI (Reuters) - Hundreds of Indians thronged the leafy streets of New Delhi on Saturday to greet Narendra Modi's triumphant march into the capital after he decimated the Nehru-Gandhi dynasty and the ruling Congress party in the biggest election victory the country has seen in 30 years.
Modi leaned far out of his car, waving a victory sign to jubilant supporters, in a drive from the airport to the headquarters of his Bharatiya Janata Party (BJP) in the center of town.
A Hindu nationalist who critics fear will be divisive and autocratic, Modi toned down religious issues in his pitch to India's 815 million voters and won the world's biggest ever election with promises of economic development for all.
The three-times chief minister of the western state of Gujarat is an outsider to Delhi's power circle. The low-caste son of a tea stall-owner, his rise to power signals the end of an era dominated by the descendants of India's first prime minister, independence hero Jawaharlal Nehru.
"Four to five generations have been wasted since 1952, this victory has been achieved after that," Modi said, in a jibe at the Nehru-Gandhi family and the Congress it dominates.
Describing himself as a "worker", he hailed grass-roots campaigners who showered him with pink rose petals as he arrived at party headquarters. There he met other party leaders and was expected to start discussions about forming a cabinet. Modi will not formally take office until after Tuesday, the party said.
Modi has given India its first parliamentary majority after 25 years of coalition governments, with his party winning more than six times the seats garnered by Congress.
With almost all 543 seats declared by Saturday morning, Modi's BJP looked set to win 282 seats, 10 more than the majority required to rule. With its allied parties, it was heading for a comfortable tally of around 337 - the clearest result since the 1984 assassination of prime minister Indira Gandhi propelled her son Rajiv to office.
During the campaign Modi was explicit about wanting to end the dominance of the Nehru-Gandhi family on Indian politics. He may have achieved the goal, with Congress reduced to just 44 seats, less than half of its previous worst showing.
Modi's landslide win gives him ample room to advance reforms started 23 years ago by current Prime Minister Manmohan Singh but which have stalled in recent years.
Despite his party's pasting, 81-year-old Singh was magnanimous in his final address to the nation on Saturday, wishing the incoming government success. Later, he tendered his resignation.
"I am confident about the future of India," he said in his televised message. "I firmly believe that the emergence of India as a major powerhouse of the evolving global economy is an idea whose time has come."
Unlike Singh and his predecessors, Modi will not have to deal with unruly partners to implement reform. That could usher in profound economic changes, with some supporters imagining him as India's answer to former British leader Margaret Thatcher.
U.S. REACHES OUT
The desire for change among the youthful electorate after a slump in economic growth, years of policy drift and a spate of corruption scandals overrode concerns about a spasm of violence against Muslims that occurred on his watch in Gujarat 12 years ago, as well as worries his pro-Hindu leanings would sideline minorities.
In his victory speech on Friday, 63-year-old Modi struck an inclusive tone, declaring that "the age of divisive politics has ended - from today onwards the politics of uniting people will begin".
"No words will be enough to salute the youth of India. They led from the front in the elections & rose above non-issues like caste & creed," Modi wrote on his Twitter page late on Friday.
In Washington, the Obama administration congratulated Modi, and said he would be granted a visa for U.S. travel. Washington denied Modi a visa in 2005 over the sectarian riots three years previously in Gujarat state, where he was chief minister.
Modi is expected to try to replicate his success in attracting investment and building infrastructure in Gujarat, the state he has governed for more than 12 years.
Betting on a Modi win, foreign investors have poured more than $16 billion into Indian stocks and bonds in the past six months and now hold over 22 percent of Mumbai-listed equities - a stake estimated by Morgan Stanley at almost $280 billion.
But with India's economy suffering its worst slowdown since the 1980s and battling high inflation, it will not be an easy task to meet the hopes of millions of Indians who have bought into the idea that Modi will quickly push their country onto the top table of global economic powers.
His party also lacks strength in the upper house of parliament, where backing is needed for legislation to pass.
When Indira Gandhi was prime minister it was often said that she was so dominant that "India is Indira, Indira is India". The Economic Times echoed that on Saturday, with a headline: "India is Modi. Modi is India."
"Modi's ability to rise from nothing to everything has demonstrated that Indians are no longer willing to accept credentials such as belonging to a dynasty or assertion of past scholarly accomplishment abroad as a substitute for persuasive argumentation: you have to perform to command respect," Jagdish Bhagwati, an eminent Indian-born economist who has positioned himself to advise the new prime minister, told Reuters in an email exchange.
(Additional reporting by Frank Jack Daniel and Aditya Kalra in New Delhi; Writing by Frank Jack Daniel; Editing by Raju Gopalakrishnan)