A week after Saudi Arabia unveiled plans to build a $500 billion futuristic megacity free from the kingdom's usual religious restrictions, there's confusion over what, exactly, will be allowed.

A video presentation last week envisaged men and women working side by side in the new city, women exercising in leotards and people playing musical instruments – activities which have traditionally been forbidden in the rest of the kingdom.

This image of an easy-going lifestyle is aimed at attracting foreign investors but, according to Crown Prince Mohammed bin Salman who is the driving force behind the project, alcohol will be banned.

The official announcement of Neom, as the city will be known, described it has having a different "governmental framework" from other parts of Saudi Arabia – suggesting that sharia-based laws will not apply. In an interview with Bloomberg, Prince Mohammed confirmed that it will have "different rules" but continued:

"We can do 98 percent of the standards applied in similar cities. But there is two percent we can’t do, like for example alcohol."

One problem with this is that it opens the door for religious elements to demand further restrictions. Conceding that alcohol can be prohibited on religious grounds will make it more difficult to resist banning other things for similar reasons.

Neom is to be built in the far northwest of Saudi Arabia, adjacent to the Jordanian border and facing Egypt across the Gulf of Aqaba where it will be linked to Egypt with a bridge. According to Prince Mohammed, this offers a neat solution to the alcohol problem (though it raises other questions about drinking and driving):

"A foreigner who desires alcohol can either go to Egypt or Jordan. So Egypt, from Tiran it’s 3.5 kilometers and from Ras Sheikh Hmeid, I think it’s 15 kilometers. If you are on the closest side it’s two minutes by car. If you are on the far side of the city it’s like 20 minutes by car. So I think it will give the foreign investor and the foreign visitor their needs without harming regulations."

When completed, Neom will allegedly be three times the size of New York and the plans say it will stretch across the border into Jordanian and Egyptian territory (though they also say it will be under Saudi sovereignty). There is no official word about how far it will extend into either country, though Jordanian media have reported that it will include the Red Sea resort of Aqaba.

It is unclear from this whether the alcohol ban will apply to the whole of Neom or just the parts of it that are on Saudi territory. If it's the latter, there will presumably have to be checkpoints inside Neom to ensure that alcohol doesn't cross over into the Saudi sector.

Alcohol is legally available in both Egypt and Jordan, so applying a ban across the whole of Neom would mean persuading them to change the law in the relevant parts of their countries.

A similar question arises over non-Muslim religions: will there be churches in Neom, or not? Islam is the only religion allowed in Saudi Arabia but Egypt and Jordan both have Christian minorities and churches are permitted.

In his interview with Bloomberg, Prince Mohammed explained that the name "Neom" was created by taking the first letter of mustaqbal (Arabic for "future") and prefixing it with "neo", which he wrongly described as the Latin word for "new". Actually, it's Greek.