In an effort to improve air quality in their respective cities, the mayors of Paris, Madris, Athens and Mexico City have moved to ban diesel vehicles from entering the metropolitan areas by the year 2025. Paris had begun making steps in improving air quality in their city by banning entry of pre-1997 cars in the vicinity.

This announcement was made during the biennial meeting of city leaders during this year's C40 Council. Headed by Paris Mayor Anne Hidalgo, the move to ban diesels in cities was spurred by emissions, particularly with nitrogen oxides (NOx). “Today, we also stand up to say we no longer tolerate air pollution and the health problems and deaths it causes – particularly for our most vulnerable citizens. Big problems like air pollution require bold action, and we call on car and bus manufacturers to join us,” said Hidalgo during the summit.

With this proposed ban, the mayors of the said cities said that they will give incentives to those who opt for alternative power vehicles. These vehicles include hybrids, plug-in hybrids, fuel cell (hydrogen) power and fully electric vehicles. The mayors are also promoting the use of public transportation, cycling and walking.

It's not just these four cities clamping down on diesels. Over in Germany, the federal council took the banning of diesels one step further. The Bundestadt recently passed a proposal to stop the sales of new combustion engine cars by 2030. Starting then, only zero-emission vehicles such as electric cars or hydrogen fuel cell-powered cars will be sold in Germany.