Arindam Bhattacharyya, an advertising executive based in Jakarta, had an unexpected wake-up call in 2024.

His parents, based in India's Kolkata city, were visiting him when his father had a health crisis. Bhattacharyya managed to get him medical care but when it was time for them to go back, he faced a question familiar to many Indians - how do you care for your parents when you can't be there in person?

Between 2020 and 2050, the number of people aged 60 and above globally is projected to double to 2.1 billion, according to the United Nations Population Fund (UNFPA). India is expected to mirror this - by 2050, one in every five Indians will be above the age of 60, close to 21% of the total population.

Until a few decades ago, there was little discussion in India on caring for elderly people as the expectation was that families would step in, the UNFPA notes, external.

This, however, has been complicated by factors including the shrinking of joint families. As younger people move away from their families, and with limited social infrastructure to support the elderly, a gap is only widening, experts say.

Some frame this as an opportunity.

Government think-tank NITI Aayog says the senior care industry in India is valued at around $7bn (£5.56bn) - it is expected to grow rapidly and offer huge opportunities for healthcare companies.

Many start-ups are already moving in. These companies are looking to address several areas including senior living, home care and technology-enabled services. While their goal is to help older adults live and age more independently, their customers are often the children of the people they help.

Bhattacharyya says he now relies on two start-ups to monitor his parents' health, coordinate care and arrange emergency medical support.

"These services are a big help but I still monitor everything closely [from Jakarta]," he said.

An area seeing an uptick is organised senior living, mainly due to higher incomes and changing family structures. But some experts believe that demand is far ahead of supply.

Companies like Manasum Senior Living, Primus Senior Living, Ananta Living and Vedaanta Senior Living are building projects especially for senior housing and care, even as there is growing interest from traditional real estate developers.

Real estate management firm Colliers International Group estimates current senior living demand at around 2-2.2 million units in India while only around 25,000 units are available.

Anantharam Varayur, a former tech executive, co-founded Manasum Senior Living after he saw many older people in India living restricted lives compared with their peers in the US.

In 2015, when he first set up a promotional stall at an event by a large Indian community in the US, hoping to draw interest from younger Indians due to their familiarity with the concept, hardly anyone came to ask questions - he thinks this was due to the "stigma" associated with leaving older family members in an "old age home", as they are traditionally called in India.

But things have changed - his company already has 900 operational units, mostly in Bengaluru and Goa, and plans to scale up to 10,000 units by 2030, including a luxury project.

They get enquiries from senior citizens whose children live abroad, couples with adult children with special needs, older single people, and even younger people planning for the future.

But there are also many older people who prefer staying in their family homes or apartments and need support.

Earlier, attendants and nurses were seen as an addition to family caregivers. Today, they are often taking on primary caregiving roles.

What was once a fragmented, hyperlocal market run by small agencies is now seeing the rise of firms that offer end-to-end home-care services and use technology to scale up. Examples include Emoha Elder Care Services, Care24 and KITES Senior Care, among others.

But given the sensitive and intimate nature of the caregiving industry, finding the right personnel and retaining them is a big challenge.

"Failure to adequately train the workforce will lead to an acute shortage of skilled people amid rising demand," warns a report by ratings firm CareEdge.

The challenge goes beyond skills. Caregivers also need thorough vetting and specialised training to support a demographic that is vulnerable to fraud, financial scams and other forms of exploitation.

NITI Aayog has recognised this issue and highlighted the need for a national caregiving policy to build a professional and inclusive caregiving ecosystem in India.

Entrepreneurs are also looking at ways to address the social and emotional needs of clients.

In 2022, former Tata Group chairman Ratan Tata's investment in start-up Goodfellows generated a lot of public interest. The company's tagline explains what it does - "Everything Grandkids Do!"

Founder Shantanu Naidu says that they are not aiming to replace family, but to fill a void by offering spirited, empathetic youth companions for elderly clients for some quality time together or even to just help them with technology.

While Naidu's start-up is tapping human emotional intelligence, some entrepreneurs are using artificial intelligence to solve real-life challenges.

In Bengaluru, companies like Kubo Care and NoBlink.ai combine AI-powered monitoring services with wall-mounted radar devices at homes to monitor people's movements to alert emergency services if they faint or fall.

Prajith Nair, co-founder of NoBlink.ai, says that they aim to "build at scale so that it is available at economical and affordable cost".

He says that the company is currently selling these systems to senior living projects at 13,500 rupees ($141.74; £106.42) per device and a monthly monitoring fee of onwards of 50 rupees per room, one tenth the price of what some similar products abroad.

But despite many start-ups aiming to keep prices competitive, affordability is a big concern.

Varayur says buying a one bedroom-hall-kitchen unit in a senior living project can cost 6m rupees, with additional payment for maintenance and food. The cost can vary according to the facilities chosen.

Demand is high, but this is out of reach for most elderly Indians.

NITI Aayog says 78% of India's elderly population is without a pension, which could restrict their ability to access these services. Households with at least one elderly person have a lower monthly per capita income of around 3,568 rupees as compared with 4,098 rupees for a unit without an elderly member.

That's why start-ups can't be the only solution, experts say.

Japan has addressed issues faced by its ageing population by introducing a mix of long-term care insurance, public nursing facilities, social exchange programmes and community-based support systems. India's neighbour China has spent years grappling with an ageing population, rolling out measures to encourage younger people to marry and boost births as its workforce shrinks.

Earlier this year, Kerala became the first Indian state to pass a landmark law for senior citizens centred on rights to affordable care, legal aid, digital inclusion and safe public spaces.

Industry experts say India still has time before it reaches a demographic crossroad. But caring for millions more elderly citizens will require robust support systems. A strong ecosystem of businesses serving senior citizens could play a role in bridging that gap.