NEW DELHI - Congress vice-president Rahul Gandhi has turned vegetarian in recent months, probably the only thing he has in common with his political adversary, Bharatiya Janata Party (BJP) leader Narendra Modi, a controversial politician two decades older.
In April, the 42-year-old Gandhi scion told an audience of business leaders that a "hero" riding a horse - an apparent reference to Mr Modi - could not solve the problems of a complicated nation of 1.2 billion people.
Mr Modi, 62, who as chief minister of Gujarat turned the state into an economic powerhouse and promises to do the same in the rest of the country if his party wins the next election and he becomes prime minister, took the verbal bait. What does a boy born with a "golden spoon in his mouth" know anyway, Mr Modi scoffed later.
One person can do a lot of things, he added.
India's two main political parties are squaring off for a tough fight next year, or earlier if snap polls are called, at a time of pessimism in Asia's third-largest economy. Large sections of Indians, who once enjoyed double-digit growth with better-paying jobs and improved lifestyles, are now worried over bread and butter issues.
Sluggish growth has brought rising youth unemployment, a fall in the value of the rupee, as well as higher food and petrol prices, with anger directed against a political class that has been unable to restore confidence.
The ruling Congress, a left-of-centre party, has been enmeshed in corruption scandals. It has also faced the exit of coalition partners such as the DMK in the south and Trinamool Congress in the east while its own ministers have been under a cloud of controversy.
On the other hand, the opposition BJP has suffered from a decade-long leadership crisis, infighting and a general lack of direction. So when Mr Modi was made the BJP's campaign committee chief on June 9, he became the unquestioned front-line prime ministerial candidate, taking the battle straight to Mr Gandhi, the Congress poll panel chief.
Mr Modi, a bespectacled, impeccably groomed politician who started out as a grassroots worker and then won three terms as chief minister of Gujarat, is pitted against Mr Gandhi, who has been pushed to the top by a party that banks on the Gandhi name to attract votes.
Political analyst and Jawaharlal Nehru University professor Chintamani Mahapatra said: "The role of personalities is also important in India even though many other issues like caste and religion matter. Rahul Gandhi is still on a learning curve and trying to understand India. Mr Modi is ahead in experience, is articulate and a seasoned political leader."
But Professor Shiv Visvanathan, a sociologist, is less charitable: "It is very simple. Modi is authoritarian and has alienated a lot of people within his party and no coalition will be easy with him. As for Rahul, at 42, he cannot behave like a youngster. Why doesn't he say what he thinks on issues now?"
India's political history has no real parallel of two more dissimilar politicians facing off. Mr Gandhi is soft-spoken, self-effacing and wary of taking charge or stating his views on issues, while his rival is aggressive, abrasive, called arrogant by some, and unapologetic about his quest for power.
Mr Modi's aggressive demeanour and impatience to get things done are traits recognised by upwardly mobile young Indians in a country where a large section of the population is under 35.
So Mr Modi is the youth icon, instead of Mr Gandhi.
But the Gujarat chief minister, the poster boy of far-right Hindu nationalists, is a divisive figure. Some party colleagues strongly believe that he cannot lead a coalition to victory, while others say he is the only one who can.
"With him at the helm, he becomes the centre of the campaign. People extol him and many more attack him. Either you love him or hate him but you can't ignore him," said BJP member G.V.L. Narasimha Rao.
"He is the only individual in the party that can maximise votes."
The Congress, the grand old party of Indian politics, has continued to dismiss the comparisons between Mr Modi and Mr Gandhi, whose political legacy the party needs to protect well beyond next year in case of a Congress defeat.
"We overestimate the role of personalities," Cabinet minister and key Congress poll strategist Jairam Ramesh said.
"This Modi versus Rahul talk trivialises a serious political conflict. It is a clash of ideologies, of competing visions, of conflicting interpretations of the past, of competing visions of how economic growth and social harmony must go hand in hand."
The Congress and the BJP may be the two main national parties, but the Indian political system is an intricate web of other smaller national and regional parties.
India, divided into large swathes by different religions, castes and communities, has seen the rise of regional parties that better serve the interests of the groups they cater to.
So the Bahujan Samaj Party led by Ms Mayawati in the populous state of Uttar Pradesh appeals to Dalits, known formerly as untouchables, while the southern parties AIADMK and DMK have sidelined the BJP and Congress in Tamil Nadu.
Victory at the polls for either the BJP or Congress depends on which party can cobble together a stronger alliance.
This is where the BJP faces a trickier situation than the Congress party. Existing allies such as the Janata Dal (United) are on the brink of ending a 17-year relationship, scared that Mr Modi, criticised for not doing much to stem the 2002 Hindu-Muslim riots in Gujarat, will damage their Muslim vote bank.
But supporters believe that Mr Modi, popular among the urban middle class, could energise the party and will help to win 160 to 180 of the 533 seats in Parliament, which would automatically attract potential allies.
Critics call that estimate unrealistic. The Congress party currently holds 206 parliamentary seats, which it won in the 2009 elections.
Mr Gandhi and Congress, on the other hand, are being watched carefully by allies such as the Samajwadi Party in Uttar Pradesh, which do not want the poor performance of the Congress-led government to rub off on them.
As the Congress-led coalition, which includes parties such as the Nationalist Congress Party and the National Conference, gets into the last year of its second term, it is dipping in the popularity ratings.
A number of opinion polls have predicted that if an election were held now, Congress would lose. But the biggest gain would go to smaller regional parties and not the BJP.
When it comes to a preferred prime ministerial candidate, Mr Modi leads the opinion polls. One poll by television channel CNN-IBN showed 38 per cent of urban voters prefer Mr Modi, while only 13 per cent prefer Mr Gandhi.
Corporate India too is firmly in Mr Modi's corner because of his success in transforming Gujarat into an economic hub and because his Gujarat government is known to move fast to help corporates to set up their business.
Keventer Group chairman M.K. Jalan said recently: "I think development matters. Political ideology does not matter to us. We want him (Modi) to be a national leader. We want him to govern India."
Congress hopes to roll out schemes such as the food security Bill, which will give two-thirds of India subsidised food grains, to consolidate its traditional vote bank among the poor and groups such as farmers. It hopes Mr Modi will have such a polarising effect that Muslims, who form around 14 per cent of the population, will vote in large numbers for Congress. In recent years, the Muslim vote has fragmented to smaller, regional parties.
As Mr Gandhi and Mr Modi square off, the rhetoric between Congress and the BJP is reaching high volume. Mr Modi is "Yamraj", the god of death in Hindu mythology, said one Congress spokesman, in a reference to the 2002 religious riots in which more than 1,000 people were killed in Gujarat under Mr Modi's rule.
It was a throwback to Congress president Sonia Gandhi calling Mr Modi a "messenger of death" some years ago. The BJP response: Don't use abusive language. For Mr Modi and his party, what matters is how they are judged against Congress by the electorate, not by their political opponents.