One recent Sunday morning, volunteers for India's main opposition party fanned out through a middle-class apartment building in the capital. They knocked on doors, guided by the most sophisticated set of analytical voter data that India had ever seen.
When a sleepy young man at one door said he favoured the party's candidate for prime minister, Narendra Modi, the volunteers pounced.
"Are you on Facebook? Twitter? Do you use WhatsApp ? … We would like to send out some political jokes, Modi messages and videos. Can you post and circulate them among your friends?" asked Mahavir Mittal, 45, a shoe box manufacturer.
Starting yesterday, millions of voters head to the polls in an election that could oust the party that has dominated India's politics for decades and show they want to move beyond traditional priorities such as caste and religion to focus on government corruption and the economy.
India's electorate is starkly different today compared with a decade ago, when Prime Minister Manmohan Singh's first coalition government came to power. About two-thirds of the population is younger than 35. Voters are more urban and connected than ever before, and per capita income has risen . Upwardly mobile urbanites make up about one-third of the electorate.
Watch: Indian voters kick off world's biggest election
To reach them, political parties are going beyond the traditional campaign rallies, packed with supporters bused in by candidates. Now, they are pursuing US-style campaign strategies, including volunteer mobilisation, social media outreach and micro-targeting of various groups such as business executives, students and retirees living in gated communities. The parties hope to engage members of India's growing middle class, who in previous elections stayed home instead of waiting in long, chaotic lines at polling stations.
The tactics are also being used to reach Indian youth. The number of first-time voters has increased from 43 million in 2009 to 101 million today, out of an eligible 814 million, according to the Election Commission of India.
In the past, voters often cast ballots along caste, religious or ethnic lines, sometimes following a village elder's orders. This benefited the governing Congress party, which has a large presence in the countryside.
That has changed. "I am impatient. Some days I feel that our old-style politics and politicians will never change, but then there are days when I feel there is still some hope for India," said Tavleen Kohli, 22, a graduate student of psychology in Gurgaon, a suburb of the capital.
"Jobs are important for me, but so is clean politics. In this election, many of my friends feel that our vote matters."
Modi, 63, has 3.66 million followers on Twitter and his campaign has drawn more than a million volunteers , a new development in a country where politicking has generally been done by party workers, called cadres. His Bharatiya Janata Party (BJP) is ahead in most polls.
His campaign highlights his record as the pro-business chief minister of the western state of Gujarat and plays down his credentials as an ardent Hindu nationalist. He is trying to capitalise on disillusionment with the current government over the slowdown in economic growth. The country's gross domestic product grew at more than 4 per cent in 2013, less than half of the increase in 2010.
Modi's followers run war rooms in three cities, with social media and speechwriting teams that can fine-tune his message for specific groups.
Indian campaigners don't have access to the vast array of consumer data that American political parties use. But Modi's campaign analysts spent months creating a database with polling information from individual precincts in the past six elections, which had to be translated from dozens of languages to identify and target potential voters.
When Mittal canvassed in central Delhi, he was equipped with voters' telephone numbers, e-mail addresses, the neighbourhoods' past voting records and an estimate of how likely individuals are to vote for Modi.
The volunteers "are the young, middle-class professionals who want to contribute, but they are not here for a lifetime. They have attached themselves to us for a few months," said Arvind Gupta, the head of the BJP's digital campaign. "We have studied [US President] Obama's election campaign strategies and observed the elections in Australia. We are taking best practices, but we are also Indian-ising it."
For example, the campaign encourages supporters to place a "missed call" of support with their cellphones as a way to generate a telephone database. The missed call is a common phenomenon in India; people ring a number and then hang up so they are not charged for the call but there's a gentle reminder that they telephoned. In this case, the campaign can text or call them back with information.
Late last year, the new Aam Aadmi Party (AAP), or Common Man Party, surprised many people with its strong showing in the Delhi state election, just a year after it was founded on an anti-corruption platform. Although its Delhi government quickly imploded, many credited the party's fast rise to its use of Obama-style tactics such as volunteer canvassing and raising money through small donations. Since then, the party has raised nearly US$3.5 million from contributions as modest as 10 rupees (about 17 US cents).
"We were a social movement before we became a political party. We set the benchmark on the use of social media for mobilising volunteers around an idea of anti-corruption," said Dilip Pandey, who supervises the campaign for AAP.
Nandan Nilekani, co-founder of global IT giant Infosys, is running for a seat in parliament as a Congress party candidate and is using micro-targeting to woo voters in the tech hub of Bangalore. His team created an app that helps volunteers track each family's political leanings and how they change. But he says there are still limits to how widely Western-style strategies can be used in India, given that just about 200 million people - fewer than 20 per cent of the population - have internet access.
While targeted messaging and outreach have proved effective, there's no Indian equivalent to the digitised US data such as voting records and credit history, Nilekani said. "There's almost no data here." Some experts say it remains to be seen how successful these new campaign strategies will be in a country where nearly 70 per cent of the population lives in rural areas, including millions of poor people.
"The importance of social media has grown, but look at the size of the population, the number of people living in villages, the number of illiterates," said Sanjay Kumar, an election expert and director of the Centre for the Study of Developing Societies.
Voters will go to the polls in phases, starting yesterday and ending on May 12, with tallying scheduled for May 16.
The Congress party, a 128-year-old monolith dominated by the descendants of the country's first prime minister, Jawaharlal Nehru, has been slower to adopt new campaign tactics. Its organisers continue to rely on traditional methods such as large-scale rallies and "road shows", in which candidates travel through villages waving from open cars.
The party's public face, Rahul Gandhi, 43, Nehru's great-grandson, is not active on social media. Recently, though, the party has tried to play catch-up to the Modi machine, redesigning its website and bringing in Matthew McGregor of the consulting firm Blue State Digital, dubbed Obama's "digital attack dog" in the 2012 campaign. After a training session with McGregor in February, the Congress party introduced a "Fact Check" feature on the website to highlight Modi's shortcomings and more controversial statements, said Gaurav Pandhi, the head of the party's volunteer social media effort.
"For far too long, the 'India lives in its villages' mindset dominated political calculations and prevented parties from addressing urban voters," Pandhi said. "But now urban India is hard to ignore."
Q&A about the election
India’s marathon nine-phase election started yesterday and ends on May 12. Hundreds of millions will cast their ballots. The following explains how it works and what is at stake.
Q. Why will it take so long?
Almost 814 million adult Indians are eligible to vote, making it the biggest election in history. Organisers say it would be impossible to operate and guard nearly 930,000 polling stations on a single day.
Q. How do people vote?
Electronic voting machines should reduce the time needed to cast a vote and allow for faster ballot counting on May 16.
Q. What’s at stake?
India is the world’s second-most populous country, a key member of the G20 global grouping and an increasingly important voice for developing countries on issues from climate change to global trade deals.
It is also home to a third of the world’s poor while being the 10th-biggest economy globally.
Surveys show that voters are fed up with corruption, worried about jobs and price rises, and ready for a new leadership after 10 years of centre-left rule by the Congress party.
Worries about India’s religious harmony have also been raised, after the ruling Congress party warned that the country under Hindu nationalist opposition front-runner Narendra Modi could see violence.
Q. How accurate are the pollsters?
They unanimously show the opposition Bharatiya Janata Party (BJP) set to be the biggest party in the next parliament, but poll projections have been wrong, most notably in 2004. It is difficult to accurately gauge the opinions of India’s mostly rural 1.2 billion people.
Q. When will we know the results?
They will be announced on May 16, four days after polls close.
Q. Is violence or corruption expected to be a major problem?
Security personnel are deployed at every polling booth, with the tightest security reserved for the restive northeastern states and northwestern Kashmir, both home to decades-old separatist movements.
There are also risks in remote Maoist-affected areas in eastern and central India.
Attempts at influencing voters through illicit freebies such as liquor and cash are routine in Indian elections, despite heavy penalties.
Q. When will a new government take office?
If no one has a majority on May 16, the president will ask the biggest party to try to put together a coalition with smaller, regional parties. This is likely to lead to days, and possibly weeks, of intense negotiations, with the BJP currently seen as being short of the required tally.