Well, let us imagine for some time that we have unlimited WiFi spectrum. But let's assume that the dipole antennas give maximum 250 meters. So in order to traverse Moscow (Yes, I said Moscow!) (about 25 km in diameter according to Wikimapia) you need 100 hops which require all equipment to not only work but to be placed in good high places. The ping times also would be quite.....
You could install a 20dB dish to access a local mesh router and it would give you about 2.5 km of distance. But it does NOT solve the problem of these 100 hops.
In order to have something better you need not a mesh but a STRUCTURE of longlinks. 2 dishes could give you 25 km (really less due to obstructions and atmospheric loss). But this structure is 1) highly visible and very suspicious for Competent Organs 2) Very expensive. Basically every node should have at least 4 longlinks and a local mesh router. It's about 2 average Russian monthly incomes + installation + construction of antennas.
There ARE such networks in Athens, Barcelona and Havana since the price of Internet is quite high there. But please take in account that Athens and Barcelona are in countries with good legal systems, and in Havana the local Competent Organs are quite sober and don't object if you don't show your dislike of Castro. I prefer not to discuss USA or Russia from this aspect; it's a hint.