India is holding a month-long celebration for Prime Minister Narendra Modi, marking his 25 years in public office. Motorcyclists are riding across the country to honour him. "Prime Minister Modi and his dedication to public service for 25 years are the inspiration for young people," said BJP member Deepesh Yadav.

Bearing water from the river Ganges, 500 motorcyclists are crossing India this month and heading to Vadnagar -- where Prime Minister Narendra Modi was born 76 years ago.

Another 500 are riding in the opposite direction to Varanasi, the Hindu holy city which is Modi's constituency, planting trees and cleaning streets in honour of his quarter of a century in public office, which will be celebrated October 7. He has led India for 12 years, after 13 years as chief minister in his home state of Gujarat.

Modi's ruling Bharatiya Janata Party is using the twin celebrations for its revered leader to try to revive its fortunes after a summer of youth protests. Candle-lighting and prayer sessions across the country marked Modi's birthday on September 17.

"Prime Minister Modi and his dedication to public service for 25 years are the inspiration for young people like me all over India," said Deepesh Yadav, 32, a member of the BJP youth wing from Gujarat, as he passed through New Delhi after joining the motorbike rally.

"What he did in the past 12 years is automatically inspiring . . . now we must do something for Mr Modi."

But the BJP cadres' enthusiasm for their leader has less of an echo on the streets, where many of India's 370mn youths are expressing anger over a broadening range of issues, including a lack of well-paid jobs and long-running sexual violence.

"Young people are not interested in the activities of mainstream politics, whether it's birthday celebrations or whatever journeys the BJP organises," said Eeshna Gupta, a 25-year-old opposition student leader in Delhi. "They are instead focused on their issues: we need jobs, social security, good education, and safety for women."

Modi and his party's youth-centric campaigns were "creating even more distance", she added.

Now serving a third consecutive term as prime minister, Modi dominates India's political landscape like no other leader this century. As well as the national government, the BJP and its allies run 22 of India's 31 states and territories with elected governments.

But mass protests over the summer by the upstart Cockroach Janta Party have cast a shadow over the celebrations in his name.

The CJP, which began as an online satirical movement but quickly morphed into a nationwide force, forced the exit in July of Modi's education minister and close ally, Dharmendra Pradhan, over problems in the national exam system.

It launched more protests on Friday in Mumbai, where thousands gathered over allegations that the nominally independent election commission has improperly excluded tens of millions of voters from electoral rolls.

"Obviously, the government is under pressure," said Pratap Bhanu Mehta, an Indian political scientist and former vice-chancellor of Ashoka University. "A lot of the accumulated problems of Indian society and the Indian economy are beginning to express themselves through protests."

Modi biographer Nilanjan Mukhopadhyay said that while there was no denying the prime minister's political achievements over a quarter of a century, the CJP protests had punctured his aura of invulnerability and "for the first time he was mocked at a mass level".

"In the last two-months-plus, Mr Modi has not been able to reinvent himself," Mukhopadhyay said.

Faced with this challenge to its leader and biggest electoral asset, the BJP is rallying its extensive grassroots operation to paint the premier as a dedicated and effective leader deserving of many more years in power.

Ram Madhav, a BJP national vice-president and former national secretary, emphasised the party's commitment to seva, selfless devotion to others, and hailed Modi as an exemplar. "He is a very motivated type of leader," Madhav told the FT. "He is not just doing his political duty. He thinks it's a spiritual commitment to the welfare of the people."

The mainly pro-government press has published birthday cover wraps with advertisements extolling Modi's virtues. The celebrations even extended abroad, with the world's tallest building, Dubai's Burj Khalifa, illuminated in the colours of the Indian flag and a "Happy Birthday" message projected on to it above a photograph of Modi.

Madhav dismissed criticism that the party was too focused on its leader. "It's not as if we're creating a personality cult," he said. "We are presenting [Modi] as an example of how a seva-minded politician should act."

Modi's birthplace in rural Gujarat has been a focus of the celebrations.

Passengers arriving at Vadnagar railway station snap selfies in front of the modest teal-coloured metal hut on the main platform, from which Modi says he helped his father serve tea as a boy chai-wallah. Outside, a giant kettle in a flower bed reinforces the message of his humble origins.

Still even in Vadnagar, where roads have been improved, a giant new archaeology museum built and public buildings associated with Modi's life renovated, some residents are sceptical about the achievements of the town's most famous son.

"There are better roads since Modi became PM and the town is a lot cleaner. Yes, the town has changed a lot but our lives haven't," said dairy farmer Vishnu Popat. "We are happy for Mr Modi and the celebrations but there are no jobs or business here. What about our children? How will they survive?"

Modi remains a formidable political operator, physically fit on a strict vegetarian diet with daily yoga exercises and no alcohol. After the youth protests, the prime minister summoned the 65-strong BJP national leadership for a meeting lasting more than four hours where he asked each to speak in turn and listened intently, participants said. Ministers have been ordered to hone their Instagram skills to project better to a youth audience.

Bhanu Mehta noted that with three years until India's next general election, Modi and the BJP had "a lot of headroom to recover in the face of widespread social discontent and protest".

But he said that despite Modi's energy, the prime minister faced a fundamental contradiction in his efforts to address youth protests.

"He's by instinct a centraliser. The power is centred in his persona. And these are governance challenges that you cannot solve by extreme centralisation," he said.