Prime Minister Narendra Modi has led his party to a landslide victory in polls in Uttar Pradesh, India's most politically important state - a win seen as an affirmation of his popularity as leader and sets the stage for his own re-election in 2019.
This is the first time in over two decades that Mr Modi's Bharatiya Janata Party (BJP) has come to power in Uttar Pradesh, where politics has been dominated by regional parties.
"It is a Modi wave," BJP Uttar Pradesh chief Keshav Prasad Maurya told reporters. "The wave, which started with the 2014 (parliamentary) elections, is continuing in 2017 and the momentum will go beyond the 2019 general election."
Mr Modi - who was the face of the BJP campaign and addressed multiple rallies - attracted voters from different castes on the back of promises of development, including better electricity supply in the country's poorest state.
The Election Commission said that partial returns showed the BJP had won by a clear majority.
It was on course to win 309 of the 403 seats at stake in the state assembly, the biggest majority for any party in the state since 1980.
Mr Modi told his 28 million followers on Twitter: "I give my heartfelt thanks to the people of Uttar Pradesh. This is a historic victory for the BJP, a victory for development and good governance."
Uttar Pradesh was among five states that went to the polls in multiple phases last month and this month. The others were Punjab, Uttarakhand, Manipur and Goa.
Uttar Pradesh, where voting took place in seven phases, was regarded as the most significant.
It is the most populous state in India with more than 204 million people and sends 80 MPs, the maximum number of any state, to the federal Parliament. The vote was also seen as a ground-level test of Mr Modi's demonetisation move.
Last November, Mr Modi demonetised the 500-rupee (S$10.60) and 1,000-rupee notes, justifying the move largely as an attempt to arrest tax evasion by Indians hoarding unaccounted cash. The decision resulted in hardship as a result of a cash crunch across the board.
The win has boosted the BJP's strength in the Upper House of Parliament, where it is in the minority and has been having difficulties in pushing through legislation. Wins in state polls determine a party's strength in the Upper House.
Many analysts agree the Uttar Pradesh win has also laid the groundwork for the BJP for the 2019 general election.
"Much more than a party victory, it is a victory of the leadership," said Dr Sandeep Shastri, a Bengaluru-based political analyst.
"The space which the BJP and Mr Modi occupy has no challenger. The opposition is in disarray. This is the semi-final ahead of the finals in 2019." He added: "Very rarely in state assembly elections do parties win without projecting a local leader like the BJP did."
Results for the four other state elections put the BJP ahead in Uttarakhand state, but in the north-eastern state of Manipur, it trailed the Congress party, which won Punjab state. The Congress pulled ahead of the BJP in Goa, but remained a few seats short of a majority.
The results were seen as another major setback for Congress vice-president Rahul Gandhi, who campaigned extensively in Uttar Pradesh but failed to leave a mark.