I find that punishment sick! I have no other words for it. In the burning sun? If I would have been your mom I would have done the same with the teacher in front of the entire school and village.
If that is the punishment for a little mistake 😡
I had strict teachers too but we were in a class with 45 and learned way more than students today, music lessons and swim class included. If you did something wrong you were placed in the corner and if you said something wrong you had to write a certain sentence down 500 times!