Just plant trees in the cities. Go and Chech what is the difference of temperature in cities with trees and without. Of course sometimes it's too late: in my hometown they cut away 40 huge trees and made a market square, "because that's what they do in Netherlands" (exact explanation of local ministry), and now you cannot pass the market square in a hot day. Installation of some sort of irrigators doesn't make difference and is not hygienic (see Legionella). They took away trees and grass and made everything concrete.

Meanwhile my parent's home is much cooler, no AC needed because they have trees between the blocks