Simple marble gravestones lie flat in the grounds of St Andrew's Church in Bandra, one of the oldest Roman Catholic places of worship in Mumbai.

The names on the tombs bear witness to the city's Portuguese heritage, as a groundsman sweeps wet leaves from generations of Da Silvas, D'Souzas, Pintos, Pereiras, Furtados and Fonsecas.

Behind the white-washed church, are newer, much smaller memorials, stacked on top of one another like drawers in a high perimeter wall bordering the sea.

Inside these 'niches' are the mortal remains of the more recently deceased, whose bones have been disinterred and replaced by those who have died in the last year or two.

The spiralling cost of land and its lack of availability is a major issue for the estimated 18 million people crammed into India's financial and entertainment capital.

But increasingly, the squeeze is affecting the city's dead, prompting changes in centuries-old rituals, forcing up the cost of burials or leading to practical solutions to tackle space constraints.

"It's an issue in all the churches. There's a lack of space," admitted Father Michael Goveas, a parish priest at St Andrew's, where flattened tombstones are found even in the corridors leading to the main church.

"We're no longer giving permission for permanent graves. Anyone who has a permanent (family) plot can still utilise them. For everyone else, we give niches," he said.

The lack of burial space, a growing problem for minority Christians and Muslims in India's fast-growing big cities as well as many countries around the world, is particularly acute in Mumbai.

The local authorities estimate that there is just 1.3 square feet (0.12 square metres) of green open space per person, making it one of the most densely-populated places in the world.

One solution submitted last year to the US-based Council on Tall Buildings and Urban Habitat suggested building a tower, with space for Christian and Muslim burials and Hindu cremations.

The idea's thrust was that traditional solutions were unlikely to succeed, as older churches - and even the newer, state-run public cemeteries in outlying districts - stop providing graves in perpetuity.

"Cemeteries have a system where they don't leave the bodies for more than two years. Then the bones are moved to an ossuary (charnel house)," said Father Anthony Charanghat, spokesman for the Archdiocese of Bombay.

One significant consequence of the space crunch is the increasing number of Catholics opting for cremation - the norm amongst Hindus - which was once viewed by the Church as a denial of the resurrection of Jesus Christ.

"You used to have to get permission (to be cremated)," said Father Michael.

"Now, it's becoming more widespread... The idea that if you burn there's no resurrection doesn't exist any more.

"If you're buried or burnt, it's the same thing."

Demand for burial plots has led some city churches to advocate the use of linen shrouds or coffins made from plywood to speed up the decomposition process, said Dolphy D'Souza, from the Bombay Catholic Sabha, a community group.

"With the sizeable increase in population and lack of space, it (burial) has become very difficult and the turnaround has become something like 18 months after the body is buried," he added.

"Sometimes they have to rush it through."

Protracted disputes have also raged over the allocation of new land reserved for burials and over the building of walls to house the disinterred bones, he added.

Undertakers say that the cost of the diminishing number of burial plots available on a 30-year lease in private cemeteries has gone up in line with sky-rocketing real estate prices.

Funeral director Dion Pinto said a basic 6.5 by three feet (1.99 by 0.9 metres) plot has risen as much as five fold in recent years.

"Six or seven years ago it was about 5,000 rupees for a plot. Now it's gone up. It's like the property rates," he added.

The situation is met with resignation by many Muslims, who face a similar squeeze on burial space.

At Bada Qabrastan, the city's largest Muslim cemetery where some 5,000 people are laid to rest beneath coconut trees, rose bushes and trellises with creeping plants, officials are matter-of-fact.

"Any Muslim can be buried here, providing they have the right paperwork from the municipal authorities," said Shakil Ahmed Shabazker, who manages the cemetery spread over eight acres (3.2 hectares) of prime real estate in south Mumbai.

"Unmarked graves of unclaimed bodies are dug up after a year. We shift the bones to one side respectfully and dig in the same place," he added.