The leaders of four major global cities said they will ban diesel vehicles by 2025. During the biennial Mayors Summit in Ciudad de México, mayors of Mexico City, Madrid, Athens and Paris made these commitments to improve air quality.

They say they will give incentives for the use of electric, hydrogen and hybrid vehicles, BBC reported. The urban leaders also added they will promote walking and cycling.

“It is no secret that in Mexico City, we grapple with the twin problems of air pollution and traffic,” stated Mayor Miguel Ángel Mancera. “By expanding alternative transportation options like our Bus Rapid Transport and subway systems while also investing in cycling infrastructure, we are working to ease congestion in our roadways and our lungs.”

In Paris, the authorities already took steps to reduce the impact of diesel vehicles. Those vehicles that were registered before 1997 are not allowed to be driven in the city, and this restriction is set to tighten each year until 2020.

“Our city is implementing a bold plan – we will progressively ban the most polluting vehicles from the roads, helping Paris citizens with concrete accompanying measures,” pointed out the city’s mayor Anne Hidalgo. “Our ambition is clear and we have started to roll it out: we want to ban diesel from our city, following the model of Tokyo, which has already done the same.”

Cutting down air pollution can also reduce the emissions that worsen global warming. According to Manuela Carmena, Madrid’s mayor, tackling air pollution can also improve the health of the public.

“The quality of the air that we breathe in our cities is directly linked to tackling climate change,” added Carmena. “As we reduce the greenhouse gas emissions generated in our cities, our air will become cleaner and our children, our grandparents and our neighbors will be healthier.”

The plans announced during the meeting are already benefiting some places. In Barcelona, the publicly available bicycles have decreased the emission of carbon dioxide by more than 9,000 tons, which is worth more than 21 million miles or 33 million kilometers driven by a vehicle.