BANGKOK • Mr Pornsak Bowornsrisuk puts up an umbrella to shield his head of thick grey hair from the blazing sunshine at the Bangkok bus terminal he manages.
"You've got to be damned tough to do this job," says the 63-year-old, who records bus arrivals and departures, and tots up the fares collected from journeys across the Thai capital.
Septuagenarian bus conductor Pranom Chartyothin moves nimbly to a door to guide students off the vehicle. She waves at the driver, 66-year-old Plang Pansaior, who glances in his rear view mirror before pulling away.
Such scenes will only become more common in Thailand as its population rapidly ages, unlike its South-east Asian neighbours with more youthful populations.
The World Bank estimates the country's working-age population will shrink by 11 per cent by 2040, the fastest contraction among the region's developing nations.
Thailand's stage of economic development, the rising cost of living and education, and a population waiting longer to get married are among the reasons it is ageing more quickly than its neighbours.
An effective contraception programme in the 1970s also played a part, says Dr Sutayut Osornprasop, a human development specialist at the World Bank in Thailand.
Thailand's fertility rate dropped to 1.5 children per woman in 2013 from 5.6 in 1970, according to United Nations data.
The government is urging businesses to hire more older people to soften the impact of the ageing workforce on productivity, as well as limit the rise in the cost of its modest pension scheme.
Thailand will have to boost productivity to foot the bill for supporting its elderly, Bank of Thailand governor Veerathai Santiprabhob told Reuters in an interview in January.
"Everyone has to be able to earn more to be able to shoulder the cost of our ageing society," he said.
The state paid 61.37 billion baht (S$2.4 billion) last year in pensions, and the cost is expected to rise by 16 per cent to 71.23 billion baht in 2020.
The government established a Department of Older Persons in March last year to tackle elderly employment and related issues.
With monthly pensions of 600 to 1,000 baht, many Thais have no choice but to keep working.
"It is tiring but we just have to keep going. There isn't anyone to take care of me," says Ms Pranom, who used to work as a cleaner, and became a bus conductor after her husband died.
Nearly 40 per cent of the 10 million Thais who are above the mandatory retirement age of 60 are still in the workforce, says Mr Anusan Thienthong, head of the Department of Older Persons, adding that the government is considering extending the retirement age for some occupations.