In Nasso (Bamidbar 7:3) we are given the concept of public and private space. Using the opinion of the Chazon Ish and Rav Moshe Feinstein if an area has a density of 8,112 people per square mile then it is a public domain. Therefore it would not be eligible for an eruv. (See the questions on this website “Does the Eruv Go Here)
Here are populations and the total square miles of a few cities. Using the standard above, and assuming an even population density through the city, which of these cites would not be eligible for an eruv.
|Tel Aviv (metro area)||1,318,300||585|
|City||Population||Squire Miles||People per SQ Mile|
|Tel Aviv (metro area)||1,318,300||585.00||2,254||Eligible|
|Greater Manchester||2,553,379||243.40||10,490||Not Eligible|