Walk down any street in central London and it will soon become apparent that it's not the cleanest city. Admittedly, it's not the worst, but we've got a long way to go.
However, newly elected London mayor Sadiq Khan plans to change that. He has launched the "most ambitious and wide-ranging plans" to clean up London's air, as he vowed to make the capital the greenest in the world.
He said it has been a "tiring" first week in his new job, and that his "feet have not touched the ground".
He visited Sir John Cass's Foundation Primary School in Aldgate, central London, on Friday, where he made his first major announcement by outlining his plans for a consultation on new policies to tackle the toxic air issue in the capital.
Khan told children who were showing him the air quality monitoring station in the school's playground that he wants to be "the mayor who cleans up the air".
He said: "I've only been in the job for a few days; I'm here to nick your ideas."
After being shown around the City of London school, Khan, a father-of-two, helped children sow seeds and plant flowers in their rooftop garden.
Within his campaign manifesto as the Labour candidate, Khan promised to restore the capital to safe and legal air quality levels.
He said: "What is quite clear from the mandate that I received last Thursday is that Londoners want a mayor to clean up in London - that is a fact.
"Almost 10,000 Londoners died last year because of our poor air - that is a fact. There are children in parts of London whose lungs are underdeveloped because of our air.
"We have had eight years of inaction, London now demands action. What I have announced today, 60 years from the Clean Air Act, is the most ambitious and wide-ranging plans to clean up our air."
Khan said the reason he is launching a consultation on the proposals is because he wants to hear from Londoners - especially if they have any plans they want him to consider.
Meanwhile, he dismissed the idea that Boris bikes should be renamed Sadiq Cycles, saying he is "not in favour of vanity projects".