The late Vann Molyvann, the doyen of modern Khmer architecture, once mused that the urban expansion of Phnom Penh should head south as that side of the city has the most favourable topography and is not prone to seasonal flooding.

Some of the capital’s most ambitious development projects are pushing the city’s limits in this direction, the grandest being ING City, a colossal satellite city project that covers an area the size of Macau. Built on a sprawling 2,572 hectares, much of it on reclaimed land, the project is being developed in four stages by local conglomerate ING Holdings.

The company has put the price tag on the satellite city at $700 million, and is bringing in private developers to construct sections according to its 2014-2020 master plan.

At the project’s core is Hun Sen Road, a 60 metre wide, 9.4 kilometre artery that opened last year and dissects the satellite city from north to south.

Many of the largest developments are along this road including R&F Magnificent Mansion, a mixed commercial and residential development announced in December. Chinese developer Guangzhou R&F Property is injecting $700 million to develop the 7.7 hectare project, which includes nearly 560,000 square metres of building area.

Further along in development is Borey Woodland, a gated residential community of townhouses and villas that began construction in October 2016, and PH Diamond Plaza, a two-storey shopping mall at the heart of Borey Peng Houth’s mixed-use development, The Star Diamond.

Chrek Soknim, CEO of Century 21 Mekong, said the southern side of Phnom Penh has high potential for growth as it is within easy reach of the city centre, has favourable topography, and has been zoned as an upscale district of malls and high-rise buildings.

“This area has been recognised as one with high potential for a long time, not only now,” he said.

One lingering concern is air pollution. Several factories in the area, mostly producing garments and foodstuffs, emit fumes with unpleasant odours or possible health risks.

However, Soknim suggested the rise in property values in the area is making it unsuitable for industry and he expects the existing factories to relocate to cheaper land further outside the capital. Most should be gone by the time ING City and other projects start seeing tenants move in.

“Typically, each construction project requires about three to five years to complete,” he said. “So the factories will have already moved by the time these projects are done.”

The massive new development on the capital’s southern frontier has enormous economic benefits, but it also comes with a social and environmental cost. More than 500 families could be displaced from their homes to make way for the ING City project, and much of the construction is on land reclaimed from Boeung Tumpun lake and Choeung Ek wetlands, which historically served as an important drainage basin for Phnom Penh.

ING Holdings could not be reached for comment. However a representative previously told The Post that the satellite city development was a long-term investment intended to turn the area into a modern city, and efforts would be made “to protect the environment and value the residents’ lifestyle”.