Candidates in three areas accounted for half of the 160 ads placed on Facebook pledging to roll back low-traffic neighbourhoods or clean air zones

Guardian graphic. Source: Guardian analysis of Facebook ad library data. Not shown: Havering 4, Southwark 3, Ealing 2, Bath and NE Somerset, Bolton, Harrow, Islington, Lambeth, Midlothian, Richmond, Tameside 1