London Mayor Boris Johnson yesterday outlined plans to make London "the cleanest, greenest city on Earth" by the 2012 Olympics. He also called for commitments from other world cities at a climate change conference in Seoul.

Leaders of the world's 40 largest cities, plus 17 affiliate municipalities, are meeting in Seoul this week for a summit on combating global warming - the third to be held since 2005.

"What we should do in Seoul is agree that we will stop the endless addiction of mankind to the internal combustion engine," said Johnson.

He told a press conference that the world's cities consume 75 percent of its energy and produce 80 percent of the emissions which cause climate change.

"The problem of our planet is an urban problem," Johnson said, calling for "serious results" in Seoul.

"I don't want to walk away with a communiqué which contains nothing but warm words and hot air... it's important we agree on some specific measures."

He said the British capital wants to use the Olympics "to drive the greening and the improvement of our city". Johnson also noted that London is committed to reduce carbon emissions by 60 percent by 2025.

Johnson said the key measure was addressing the problems relating to domestic and commercial buildings, which accounted for 70 percent of carbon dioxide emissions in London.

This involved retrofitting - installing lagging - in large numbers of public buildings.

Johnson proclaimed himself a "passionate cyclist" and said he would push ahead with cycle super-highways around London.

He also called for "real progress" by cities worldwide towards the electrification of municipal fleets and other vehicles. "That's one of the things we are hoping to achieve in Seoul."

London's air quality problem, he said, was caused by vehicle emissions from 8,300 antiquated diesel buses, which could be replaced by low-carbon vehicles.

There were also 32,000 taxis running on diesel fuel, which could be replaced by electric vehicles.

Johnson said there would be a substantial program in the next few years to produce a "cleaner, greener" bus for his city. "The age of the diesel-emitting bus has got to be over in London."