The fate of a large green space in the middle of one of the world's most built-up cities is pitting communities and conservationists against developers and cash-strapped authorities in a battle that is increasingly common in Asia. The Makkasan area in central Bangkok, measuring about 80 hectares - or about 80 rugby fields - houses a train station, a workshop, warehouses and some homes in a green expanse that stands in contrast to the sleek high-rise buildings all around. Debates around the Makkasan land - owned by the State Railway of Thailand (SRT) - have raged for years as it is the final remaining open space in a city with too few parks. "It is the last big space we have in Bangkok, and our last opportunity to create a big green space for the people. We must not waste it," said Pongkwan Lassus, an architect and designer. "Besides the space, many of the buildings have historic and architectural value. We must conserve this heritage for future generations, not knock it all down for malls," she said. Across booming Asian cities, open spaces and older buildings are making way for expressways and modern office and apartment towers that critics say rob them of their character, widen inequalities and magnify the harmful effects of urban sprawl. Some cities are adopting a more unusual approach to growing demand for diminishing space. This year Singapore is set to unveil an Underground Master Plan. With some 5.6 million people in an area three-fifths the size of New York City - and with the population estimated to grow to 6.9 million by 2030 - the island nation is fast running out of space. Singapore has been reclaiming land for decades, but that is increasingly unsustainable due to rising sea levels and other impacts of climate change, according to Reuters. So the city is going underground. It has already moved some infrastructure and utilities below ground, including train lines, retail, pedestrian walkways, a five-lane highway and air-conditioning cooling pipes. It also stores fuel and ammunition underground. Now, the city wants to go further. "Given Singapore's limited land, we need to make better use of our surface land and systematically consider how to tap our underground space for future needs," said Ler Seng Ann, a group director at the Urban Redevelopment Authority (URA). "Currently, our focus is on using underground space for utility, transport, storage and industrial facilities to free up surface land for housing, offices, community uses and greenery, to enhance liveability," he said. The Underground Master Plan will feature pilot areas, with ideas including data centres, utility plants, bus depots, a deep-tunnel sewerage system, warehousing and water reservoirs. There are no plans to move homes or offices below ground. In Bangkok, meanwhile, a community of more than 300 people living next to an old fort in Bangkok were evicted last year and their traditional wooden buildings razed to make way for a public park that critics say is meant only to impress tourists. Authorities are also clearing vendors and food stalls from the pavements, and removing shops and shanties along the Chao Phraya river in a bid to modernise Bangkok. Civic groups say the evictions and redevelopment plans mostly target poor communities who have no formal rights over the land or spaces they occupy in the congested city. Authorities say they are removing encroachers to improve accessibility and liveability for residents. That promise is being tested as a plan for Makkasan's redevelopment is finalised. "We have asked a consultant to study the best use of the land, and we will decide accordingly," said Siriphong Preutthipan, a deputy governor of SRT. "We are aware of the various demands for green space, a museum and commercial developments. We will consider all of them and see what makes best sense, the best use of the land," he said. With some 20 million visitors last year, Bangkok was named the world's most visited city, beating favourites including London, Paris and New York, according to the Mastercard Index. Yet the Thai capital was ranked a lowly 132 of 231 on a survey of liveable cities, which measures factors such as public transportation, natural environment and air pollution. Bangkok has another unhappy distinction - among the lowest ratios of green space: just 3.3 square metres per person compared to New York City's 23.1 square metres and Singapore's 66, the Siemens-sponsored Green City Index showed. Everywhere, space is at a premium. While Singapore is clearing cemeteries for highways and apartments, planners in other Asian cities are converting "dead spaces" underneath bridges and flyovers into walkways and bike trails. The Makkasan land provides a unique opportunity, said Yossapon Boonsom at Bangkok landscape architecture firm Shma. "It is prime area in the middle of the city, so it has high economic value. But we have to decide: do we need yet another mall - or a park?" he said. "We get so few chances to develop a large space like this in the centre of the city. It is a chance for us to imagine and plan a better outcome: can we combine the need for greenery and open spaces with the need to monetise the land?" A 2005 plan had proposed twin 99-storey towers for offices and apartments, along with malls and conference facilities. There was even talk of locating Thailand's first casino there. But the plan was shelved due to concerns about increased congestion in a city already notorious for traffic snarl-ups. In 2015, the military government asked SRT to lease the Makkasan land to the finance ministry to clear some of its debt, as part of a plan to get better returns from state land. At the time, the finance ministry said two-thirds of the land would be used for roads and commercial developments, with the remainder reserved for a rail museum and a green zone. But a year later, SRT said it would redevelop Makkasan by itself. A plan will be finalised this year, said Mr Siriphong. It is an unusual conundrum for SRT, said Ruth Banomyong, head of the logistics and transport department at Thammasat University in Bangkok. "Public agencies, especially land-owning agencies, are something of an oxymoron: they do not always consider the public need for sustainable and responsible development versus the need for monetisation," he said. The Makkasan land was gifted to the railway authority by revered King Chulalongkorn more than 100 years ago. The country's first railway line was inaugurated during his reign. Today, Makkasan station connects to the airport rail line and is one of the stops on the proposed high-speed railway that will link three major airports in one of the country's biggest infrastructure projects. At the large workshop, a few hundred people build, paint and repair coaches. The facility might be relocated when the land is redeveloped, said Mr Siriphong. Much of the rest of the land is largely abandoned, except for several rusting wagons, which have earned the area the nickname "train cemetery". A group of Bangkok residents had launched a social media campaign called the Makkasan Hope project to push for a park, a rail museum and the preservation of many of the old buildings. If developed as a park, it would be Bangkok's biggest. "The land was intended for public purpose and public good; we cannot subvert that and make it all for commercial gain, especially when we have no open spaces left," said Ms Pongkwan. "This could be Bangkok's own Central Park. What can be a better use of the land?"