inches chest most probably. If you wear Medium in USA, then buy Large in India. for small in USA, purchase medium in India. In USA, everything is different as they want to be different .:P
I don't know what is wrong with the table, it is so clear for all Indians and also foreigners. It is the same size outside too. Check what is your t-shirt size and buy whatever size you want, if it is small go get a bigger size, the prize is not as expensive as the t-shirts you get in US or Europe (club shirts)
Comments
This link will help
http://www.usatourist.com/english/traveltips/shopping/shopping-mens-sizes.html
Away Day Blues: Watching Bengaluru FC in action at Manjeri
BFC fans away trip to Manjeri
http://www.sportskeeda.com/2014/01/30/diary-away-trip-watch-bengaluru-fc-federation-cup-east-bengal/