It is one of India's most populous and politically important states and Prime Minister Narendra Modi is hoping to win over voters with the promise of attracting businesses and the lure of cash for infrastructure projects.
The eastern state of Bihar goes to the polls in October and November and a win for Mr Modi's ruling Bharatiya Janata Party (BJP) will be a major boost, particularly with his reform agenda stalled by opposition protests in the federal Parliament over a series of scandals.
The polls will be a test of his popularity but to win, he will need to give the state significant investment. Mr Modi has promised to give more than 500 billion rupees (S$10.8 billion) as an economic package in the coming weeks.
"He has a strong constituency in Bihar which supports him... He has not given anything tangible to Bihar," said Dr Saibal Gupta of Bihar's Asian Development Research Institute.
The third-most populous state in a country of 103 million people is also one of India's poorest. It is part of the cow belt that has always influenced federal politics and is therefore crucial to any national ruling party.
The state has 40 seats in the federal Parliament, and with neighbouring Uttar Pradesh, which has 80 seats, they make up a sizeable chunk in the 543-seat Lok Sabha, or Lower House. The BJP already has the majority of Bihar's federal Parliament seats but not in the state assembly. It faces a tough fight against an alliance of three regional parties and the Congress led by Chief Minister Nitish Kumar, who leads the Janata Dal (United).
Mr Kumar - who quit an alliance with the BJP in 2013, fearing Mr Modi as Prime Minister would hurt his Muslim voter base - has changed the face of Bihar over the past decade, cracking down on criminal gangs, building a network of roads, improving healthcare and introducing schemes such as free bicycles for girls as part of his education reforms. Growth rose to 11 per cent a year from 3 per cent before he came to power.
At a public meeting last month, Mr Modi said the development of Bihar was a "prime agenda" and vowed to give federal funds soon to develop infrastructure. Days after the meeting, his speech is still being aired in dozens of villages, some with no electricity or TV reception, from 100 video vans fitted with large projection screens.
This month, Mr Modi will address three rallies, with one scheduled for Sunday.
A poll by ABP News-Nielsen said Mr Kumar's alliance would get 129 seats, while the BJP alliance would get 112 seats of the 243-seat assembly. Currently, Janata Dal (United) has 115 seats, BJP 91, Congress four and Rashtriya Janata Dal 22.
Caste will also play a major role in the election. Mr Kumar's alliance has a combination of lower-caste and Muslim votes, while the BJP is trying to stitch up support among the lower and upper castes.
Bihar regional chieftains are not far behind in the campaigning. Mr Kumar has said his people will campaign on bicycles, while ally Lalu Prasad Yadav of the Rashtriya Janata Dal has hired more than 1,000 horse- drawn carts. "The BJP has the funds and money. We will form the government because we have done the development work, which is the biggest election issue today," said Janata Dal (United) general secretary Javed Raza.