With so much at stake, Modi has personally led the campaigning for his right-wing Bharatiya Janata Party (BJP), which won big in the 2014 general election. Photograph: (AFP)
Voting in Uttar Pradesh is a key test of Modi's popularity after his demonetisation move which hit poor rural community of UP very badly
As his helicopter swooped down for a rally the crowds cheered and waved at the leader of India's most populous state, where millions will vote on Saturday in a key test of Prime Minister Narendra Modi's popularity.
The northern state of Uttar Pradesh is home to over 200 million people -- more than the entire population of Brazil -- and polls there are seen as a bellwether of national politics.
Voting in the vast state, which sends the largest share of MPs to both houses of parliament in Delhi, will be staggered over several weeks with results out on March 11.
With so much at stake, Modi has personally led the campaigning for his right-wing Bharatiya Janata Party (BJP), which won big in the 2014 general election.
The vote is seen as a key test of his popularity after a controversial ban on high-value notes that was aimed at combating tax evasion by the rich but has also hit poor rural communities in UP hard.
He faces strong competition from the state's youthful and popular current Chief Minister Akhilesh Yadav, campaigning in a tie-up with the BJP's ailing national rivals the Congress Party.
Political analyst RP Mamgain told AFP the elections were a "litmus test" for the BJP after nearly three years in power.
"People are really looking forward to see what all they have managed to do, and their assessment will be reflected in the UP election," said Mamgain, professor at the Giri Institute of Development Studies in state capital Lucknow.
"It is a kind of a litmus test for them, on whether they delivered on jobs, urban and rural development."
It also offers a chance for the BJP to gain more seats in the upper house, which has blocked some of its planned reforms.
Yadav denounced the cash ban at a series of rallies this week attended by well-wishers -- some perched on trees to get a glimpse of the leader.
"Demonetisation didn't help anyone," the 43-year-old told AFP.
"This step has been a huge loss for the country whose consequences can't be seen at the moment.
"But it will become apparent in days to come because our economy, our labour, our manufacturing have been hit badly."
The government has conceded that the drive will hit national growth but says it will ultimately benefit the economy by bringing hidden wealth back into the system.
Analysts said it was unlikely to dent the BJP's election prospects because bank lines have eased. Anecdotal evidence suggests the policy may actually have boosted Modi's popularity in poor communities because it is viewed as hitting the rich.
"People by-and-large have appreciated Modi's intentions. Demonetisation has lost its sting, it's become a non-issue now," Anil Verma, director of the Uttar Pradesh-based Centre for the Study of Society and Politics, told AFP.
Pollsters are divided on who will win, with some forecasting a hung assembly. Low-caste leader Mayawati's Bahujan Samaj Party is expected to take third place, sweeping much of the Dalit vote.
Yadav, who became India's youngest chief minister in 2012, is hoping to win the support of Uttar Pradesh's youth after wresting control of the Samajwadi Party from his ageing father in a bitter months-long battle.
He has campaigned with the Congress second-in-command Rahul Gandhi, 46, with both leaders projecting themselves as modern agents of change in a state where religion and caste have generally dominated campaigns.
"When a young person sees that there is young leadership, somewhere or the other he will feel that this leadership will understand his particular problems like wages and jobs and will help him fulfil his dreams and ambitions," said Akhilesh.
Analysts say Gandhi, likely to be the next Congress leader, desperately needs a win to boost his lacklustre reputation after defeat at the 2014 polls.
"Congress is almost a dead party," Mamgain told AFP. "On its own, Congress is not even considered as a real alternative."