Through the targets in C40’s Clean Construction Declaration, the mayors pledged to revolutionize the global construction industry and shift it towards a more sustainable future, to achieve "a thriving, resilient and healthy life for everyone in our cities, especially our most vulnerable communities". 

According to the press release, the construction industry in its current form is responsible for more than 23% of the world’s GHG emissions and 30% of global resource consumption.

If the construction industry continues to take a business as usual approach, the world is on track for a global temperature increase of 3°C. 

"Budapest is a beautiful and exciting city with an incredible historical heritage and great architecture that we all adore," said Gergely Karácsony, Mayor of Budapest. 

"This, however, means a large building stock with rather poor energy performance and high GHG emissions, which have been worsened by the rapidly increasing traffic during the last couple of years.

"By declaring a climate emergency as one of our first measures after taking office a year ago, the Municipality of Budapest has committed itself to take active steps to reduce emissions in the city.

Embodied emissions in construction activities and materials are uncharted areas, where large mitigation potential can certainly be found. Budapest wants to find its way to mobilize its ecosystem to make significant improvement in this field, which is why the city is delighted to be signing on C40ʼs Clean Construction Declaration," he added.

The declaration sets targets to develop net-zero emission buildings and infrastructure of the future by:

• Reducing embodied emissions by at least 50% for all new buildings and retrofits by 2030.

• Reducing embodied emissions by at least 50% of all infrastructure projects by 2030.

• Procuring and when possible using only zero-emission construction machinery from 2025.

The declaration also calls for innovation and collaboration across cities, businesses, regional, national, and supranational government, and industry.

It also commits cities to repurposing and retrofitting building stock to make better use of the buildings and infrastructure that currently exist. 

The mayors also committed to lead by example on clean construction, using their purchasing power and normalizing the use of zero-emission construction machinery, and demanding transparency and accountability in their supply chains.

They aim to achieve this by embedding clean construction policies into design and planning, procurement, and contracting processes, as well as building codes. By signing the declaration, mayors promised to approve at least one net-zero emission flagship construction project by 2025 and to produce annual reports on their progress.