The London Marathon, set to attract 50,000 runners on Sunday, took several steps to lower its carbon footprint, including charging foreign entrants who had to travel to the city a $32 fee (26 pounds) as part of their entry applications.

A 2013 photo of Britain’s Prince Harry (left) and Richard Branson (right), the CEO of Virgin, posing on the podium with London Marathon winners on the Mall in central London. Source: Reuters

“I’d say absolutely, (sustainability) is something that has become much more important, whether it’s the participants, to sponsors, to partners,” said Kate Chapman, the London Marathon’s sustainability adviser, according to a Reuters story.

Travel has the largest environmental impact on large gatherings such as marathons, the story said.

In another environmentally friendly step, 2,500 runners chose to have trees planted instead of accepting an official race T-short.

However, the Reuters story said the medals that the London Marathon will be handing out to the thousands of runners will not be recyclable.

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