NEW DELHI - The return to power of the Bharatiya Janata Party (BJP) in India's eastern state of Bihar is a big boost for Prime Minister Narendra Modi, with the result being being seen as a signal by voters that he is the best option for tackling the Covid-19 pandemic and its economic fallout.

The BJP alliance, which included the Janata Dal-United (JDU), emerged the winner in the tightly contested poll in which the Rashtriya Janata Dal (RJD), led by a 30-year-old political novice, mounted a credible challenge.

The RJD-led alliance known as the Mahagathbandhan under Mr Tejashwi Yadav won 110 seats. Now regarded as the political star in the election, his RJD emerged as the largest single party, securing 75 seats in the 243-seat assembly.

It was the BJP, however, which was the biggest winner, converting its status from a junior ally and a side player in Bihar politics to grab centrestage in the state.

It helped pull the ruling National Democratic Alliance (NDA) to victory. It won 125 seats - three more than needed for a majority - with the BJP taking 74 seats and the JDU 43.

The poll outcome followed the nationwide lockdown imposed by Mr Modi, which hit Bihar severely since hundreds of thousands of its migrant workers were left jobless and stranded throughout the country. The state is among the poorest in India.

The blowback from the lockdown had an impact on JDU leader and long-time Bihar chief minister Nitish Kumar, who had to deal with anti-incumbency sentiment among voters angry with him for failing to protect the migrant workers.

But analysts said the vote was also for the BJP and Mr Modi although other factors, including caste, played a role.

"It's increasingly clear that the Modi factor and the BJP propelled the vote in favour of the NDA in Bihar The alliance was pulled down by the JDU," said political scientist Sandeep Shastri.

"Though unemployment and development were the main issues highlighted, the same voters believed the NDA could solve all problems related to unemployment, The Mahagathbandhan (opposition alliance) was not able to convince voters it could solve the problem even though they raised the issue," he added.

The RJD had promised 10 million jobs if it came to power.

Dr Rahul Verma, a Fellow at Centre for Policy Research, noted that Mr Modi had successfully managed to convince voters that he was doing his best during the pandemic with a slew of welfare schemes for the poor.

Bihar is part of the Hindi heartland that has been the foundation of support for the BJP. But the party has struggled for years to gain a bigger foothold in the state, mostly it has had to piggy-back on the JDU which, along with a clutch of other regional parties, have held sway.

The BJP's political presence has now been strengthened in the state which has over 100 million people.

Tweeting after the results were known, Mr Modi said that the poor and women in Bihar had helped propel the ruling alliance to victory.

"Today, Bihar has told the world again how democracy is strengthened. A record number of poor, deprived and women of Bihar also voted and today have also given their decisive decision for development," Mr Modi tweeted in Hindi.

"The poor in villages, farmers, labourers, merchants, shopkeepers and every section of Bihar have relied on the NDA's mantra of 'sabka saath, sabka vikas, sabka vishwas'."

He was referring to a BJP slogan in Hindi which translates to "Together, for everyone's growth, with everyone's trust".

Still the RJD has challenged the poll results even as the Election Commission denied any impropriety.

While the Bihar vote is a boost to the BJP, the party faces tough state elections next year in West Bengal, Tamil Nadu and Kerala where regional parties are particularly strong.

In Tamil Nadu, the main electoral battle is between the ruling Dravida Munnetra Kazhagam (DMK) and the All India Anna Dravida Munnetra Kazhagam (AIADMK). The BJP is eyeing an alliance with the latter.

In West Bengal, the ruling Trinamool Congress (TMC) led by Ms Mamata Bannerjee is mounting a major challenge to the BJP.

"I think the BJP will be buoyed up. But in terms of West Bengal, it is a different ball game. The TMC spread across the state is much wider, much stronger and more visible as opposed to the opposition alliance in Bihar," said Dr Shastri

"And the BJP continues to be a marginal force in Tamil Nadu and Kerala. In Tamil Nadu, much will depend on alliances that are formed."

Dr Verma said: "The most important and most difficult election is going to be Bengal. For the BJP, it will be the prize catch of this term for Prime Minister Modi. The victory (in Bihar) creates a more enthused cadre base and takes the attack on the opposition to a higher pitch."