Have you ever run a 10 km marathon?

Running is an increasingly popular hobby in India as people get more health-conscious and realise that physical exercise is as important as a good diet. And for those who are competitive, or those who just like the thrill of running with hundreds of other people, there are many road races to choose from, at least in the big cities. You can choose from among a range of distances to run, depending on your ability, with the most common being 5 km (or 5K, as they usually say), 10 km, half marathon and marathon. 

But, what is a 10 km marathon that I sometimes read about, like in the following tweets?

Sh Sanjeeva Kumar, AS& DG #NACO with participants running for 10k marathon at Jawahar Lal Nehru stadium, for children living with #HIV. He flagged off the marathon along with MP, #RajyaSabha Sh @sachin_rt. pic.twitter.com/LUv4RTrutz

— Ministry of Health (@MoHFW_INDIA) February 25, 2018

The fine and gorgeous @macynyman, actress and daughter to Andy, is running a 10k marathon for cancer research. In case you’re feeling even a bit generous: https://t.co/wMAUgigwFC

— Derren Brown (@DerrenBrown) April 16, 2018

We'd like to say a huge "Thank you!" to Danny Burkhill who ran the Sheffield 10k Marathon (in a panda head costume) and raised a fantastic £83.27 for us. We really appreciate your support Danny. <3 :D #Sheffield pic.twitter.com/f4oBSNSwjx

— RSPCA Sheffield (@RSPCASheffield) November 4, 2018

Over 1500 enthusiastic Bengalureans from all age groups participated in the 5k and 10K marathon. The run was organised to create an awareness on importance of Education and fitness.#RunBengaluru#RunToEducate pic.twitter.com/m7LidsSTbK

— NEWS9 (@NEWS9TWEETS) December 2, 2018

#XAthon, a 10K marathon where the amount raised through registrations was donated for a cause

More - https://t.co/DyRcr21L5p#Xpressions17 pic.twitter.com/J0V7fet8uZ

— XIMB (@ximbee) October 16, 2017

Vicky Vantoch is a amazing woman. She ran a 10k marathon yesterday. Shes not only incredibly smart but she is a great athlete

— ElizabethO #BeAMisha (@eorozco2720) October 8, 2017

Some people seem to think that a road race of any distance is a marathon. They are mistaken. Only a race measuring 42.195 km is called a marathon and, not surprisingly, a half marathon covers half that distance: 21.0975 km. Hence, a 10K marathon makes no sense.