However, 300,000 t0ns of clothing go to landfill in the UK each year (The Economist) and many runners don't use their race t-shirts, disposing of them after the race, which adds to the textile waste in landfill.
Manchester Half Marathon decided to do away with T-shirts completely in 2019, after recognising that the 100kg of left over t shirts from their 2018 race was not okay.
Running solo in your own city or town is definitely not the same as travelling to New York or London to race with thousands of other runners from all over the world, BUT a virtual race may be something to consider for those who want to reduce their carbon footprint or to gain confidence in racing without the pressure.
As things go back to normal post Covid it may be possible to link up with local groups of runners or friends, who also want to run virtually, and take part in a big event but run at home.