Tfl, the company that runs public transport in the city, said it supports the mayor's attempts to make London healthier.
The Mayor of London has set out a new environment strategy to make the capital the greenest city in the world by 2050.
The scheme is backed by child health experts but the Advertising Association, which represents the industry, said it would have little impact. That is why I'm proposing to ban adverts for harmful junk food from our entire Tube and bus network.
Shockingly, nearly 40% of 10 and 11-year-olds living in the capital are either overweight or obese.
"If we don't take bold steps to cut child obesity in London we'll be letting young people down and placing a huge strain on the NHS for years to come".
Rise in overdose deaths in BC
Kamloops has seen 12 people die after overdosing so far this year, putting the city on pace for its highest total ever. The coroner says more than 1,400 residents died from suspected illicit drug overdoses a year ago .
The draft London Food Strategy also includes a proposal to ban new hot food takeaways from opening within 400 metres of schools.
Khan is consulting on the plans that would see adverts for unhealthy food and drink that are high in fat, salt or sugar banned across the entire Transport for London network, including London Underground, Overground and the capital's buses and bus shelters.
The strategy comes almost two years after the prime minister watered down plans to tackle obesity, throwing out restrictions on junk food averts and promotions in supermarkets.
Mr Khan would target adverts for food and drinks high in fat, salt or sugar.
Cancer Research UK's director of cancer prevention, Alison Cox, said it would be "a really great step for London", where junk food advertising dominates in several boroughs.
The latest ban will now go out to consultation but has already been welcomed by some celebrities and proponents of big state interference, including chef Jamie Oliver.