From the diarrhoea often experienced foreign travellers to India, not specifically the city of Delhi which was probably chosen as it rhymes with belly.
"delhi-belly." YourDictionary, n.d. Web. 24 June 2018. <http://www.yourdictionary.com/delhi-belly>.
delhi-belly. (n.d.). Retrieved June 24th, 2018, from http://www.yourdictionary.com/delhi-belly
Do you use YourDictionary every day? If not, remember that it is never to late to do so!
Let us be there for you: