Just 24 hours ahead of 10:10:10 - The Global Day Of Doing, we have some massive news. And we mean MASSIVE. Mexico City, home to 21.2million people, has signed up to 10:10.

The Mayor of Mexico City, Marcelo Ebrard, signed the commitment at an event at the City Hall on Thursday. The city will be taking a number of major measures to reduce carbon emissions by 5%, and will be encouraging its citizens to match that pledge. The city's plans include:

• The opening of a new third line of the Metrobus system, which will cut 35,000 tonnes of CO2.
• A programme to replace the city's taxis, set to save another 100,000 tonnes.
• Building sustainable homes.
• Large scale water-saving and methane-capture programmes.

Alongside the city's own actions, the mayor asked Mexico City's population to reduce their electricity and water use and make more journeys by bicycle and public transport instead of by car.

Marcelo Ebrard stressed the importance of the commitment, pointing out that in the last century Mexico City's average temperature had risen by 3ºC.

Marcelo Quintanilla, 10:10's man in Mexico, also spoke at the event. He thanked the city for taking action on climate change and said they were joining over 7,000 events taking place in 188 countries for 10:10:10.

Keep watching the site for more news as it comes in.