Come September, youth development officer Shah Reza's family will receive a letter notifying them that his grandfather's remains will be reinterred elsewhere in Choa Chu Kang Cemetery.

His grandfather's grave is among some 80,500 Muslim and Chinese graves that will make way for the expansion of Tengah Air Base, as announced by the authorities last Tuesday. This, in turn, is to accommodate the relocation of Paya Lebar Air Base from 2030.

Though exhumations being done en masse are common here - part of a policy that sees those who have been buried for 15 years make way for newer "occupants" - the latest exercise will remove a third of the cemetery's 318ha grounds.

The news has left Mr Shah, 28, wondering: "Will we have to bury our loved ones on islands some day?" he said. Mr Shah, whose grandfather died in the 1970s, is concerned that with the shrinking of the cemetery - the biggest and only active one - Singapore may run out of burial space.

Of the 20,017 people who died last year, about 20 per cent - around 3,700 - were buried. Of these, nine in 10 were from religious groups where burial is compulsory, like Islam, which requires its adherents to bury their dead as soon as possible, and their bodies left intact, as a sign of respect.

The National Environment Agency (NEA), which manages the cemetery, said there is sufficient space for now and that it would "continue to work with land-use planners to ensure sufficiency of land ahead of public demand for after-death services".

Previous media reports said the cemetery, at its current size, could be used for burials until 2130. The NEA did not give an updated estimated year with the smaller space.

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But it added that even with the expansion of the military air base, "there is sufficient cemetery land to meet burial demands in the foreseeable future as the Government has already put in place measures to extend the lifespan of the cemetery".

A crypt burial system - where prefabricated concrete graves are aligned in a grid - was introduced in 2007 to intensify use of limited land.

Under the 15-year burial policy implemented since 1998, those whose religion mandates burial can be re-buried in smaller plots. The remains of up to eight people can be buried in the same space that fits a newly interred coffin for one.

About 5 per cent of Choa Chu Kang Cemetery is used for such reinterred remains, with the proportion set to grow over time, the NEA said. Those who do not need to be re-buried are cremated, and their ashes reinterred in a niche.

More people are now opting for cremation. Nearly all - 97 per cent - of those who can opt for cremation currently do so, compared with 93 per cent in 2005, said NEA.

It is also significantly cheaper to cremate a loved one. An adult cremation costs $100, compared with $315 to bury someone whose religion requires it and $940 for someone whose religion does not. These rates have remained the same for at least the past decade.

There is no lack of space in Singapore's columbariums too. The Government's 325,000 niches are about half-filled, and several private columbarium operators The Sunday Times spoke to said there are enough niches for three to four decades.

Venerable Seck Kwang Phing, president of the Singapore Buddhist Federation, said while some older Chinese may think a burial means a more restful afterlife, most have come to embrace cremation as part of the death rites here.

"It is more important to be filial to your parents while they are alive than to bury them in an attempt to give them peace," he said.

Editor Jonathan Ho, 38, a father of two girls aged three and four, said he would probably opt for cremation for himself "as it is the practical choice in Singapore" but a part of him wished burial was an option.

"The idea of my two daughters visiting their dad by his headstone is a nicer image than them going to a columbarium to look for my nook in a wall," he said.