The response to our arresting outdoor advertising and social campaign showcasing the Mayor of London’s commitment to clean up London’s air was immediate. The Mayor of London’s Clean Air website received huge volumes of traffic from people interested in understanding the subject better, as well as checking their vehicle status.


The Mayor of London is committed to cleaning up London’s air, not just to meet minimum EU emissions standards but because research has proved that the city’s air pollution is dangerously high, particularly for young children and those with respiratory problems. In December 2017 the GLA launched its T (toxicity) Charge, a £10 supplement on top of the normal daily congestion charge, aimed at deterring motorists with older or higher polluting vehicles from driving in central London. Buses and taxis have already been forced to change.

Four was tasked with creating an outdoor and social campaign to help drive awareness of this and particularly to help drivers recognise why it needs to be implemented. Our primary objective was to increase understanding and get drivers to visit the website to check if their vehicles were affected. We needed to achieve this in the face of some opposition to the charge being an additional charge on Londoners.

Planning and thinking

Through our insights, we concluded that simply reminding people that London’s air was polluted would not be sufficient to get their attention. We needed something visually striking that could show the polluted air in the context of everyday items.


We created a series of images showing the effects of pollution including a baby’s bottle, a pint of beer, a takeaway coffee and a child’s drinking cup. These images were used on a poster campaign in busy transport and underground locations, as well as on Facebook, Twitter and Instagram.

Both London and national press covered the campaign, describing the images as ‘gross’. The volume of conversation on social media demonstrated how strongly people feel about London’s dirty air, with enthusiastic support of the campaign as well as the Mayor of London’s policy.

Dirty blackened baby bottle
Dirty baby bottle with soot
Pint of Beer with black dirty foam
Coffee with dirty foam