Car free sounds good but how are big and heavy objects going to be delivered to the various homes and businesses? How would delivery vans get around and deliver to peoples doors?

There is a phrase that "cities are the mess left over from people making money". How are people going to get rich by living in The Line? One of the reasons people like cities is that they are cultural, with theaters, exhibitions, the Arts, conferences and a political centre. Where are the cultural hubs?

Where are the airports? If people are going to live in the city there will need to be exceptional transport links to other cities

The marina at the end shows large superyacht diesel guzzling powerboats! Ooops, if the city is to be zero carbon emissions then they all need to be carbon neutral sailboats!