I'm Indian. We also learned that Carbon dating was a thing somewhere between Middle School and High School. I also believe that the reference to isotopes was hyperbolic and that he actually wanted to talk about the fact that we teach the basics of Nuclear fission, fusion and radioactive decay in high school. [1]

In hindsight, it's funny that we use radioactive decay as one of the filters for an entrance exam for University. [2]

1 - https://ncert.nic.in/textbook/pdf/leph205.pdf

2 - https://en.wikipedia.org/wiki/Joint_Entrance_Examination