The declaration comes just four days before national governments are set to water down proposed EU caps on air pollution at a meeting in Brussels. Authorities from European cities most affected by air pollution have been putting pressure on national governments to change course. But proposed stricter EU pollution limits are set to be blocked by the United Kingdom, France, Italy, Poland and a handful of other EU countries in a vote on Friday.
The European Commission, the EU's executive branch, proposed the tighter air pollution limits last year, and the European Parliament have approved these. But national governments have the final say. On the same day of the pact's signature, mayors of the French and British capitals published a joint letter to national governments asking them to stick with the more ambitious proposal.
"Estimations by the European Commission suggest that weaker national emissions ceilings would lead to about 16,000 extra deaths in the EU every year," says the letter, signed by Paris mayor Anne Hidalgo and the new London mayor Sadiq Khan. "This is not acceptable and we require our governments to follow the bold lead taken by our cities in tackling this issue."