Euro 1, 2, 3 vs Bharat Standard 1, 2, 3

Bharat Stage III norms kick in from April next year nationwide.

Does this mean those people having BS II cars won't be able to sell their cars in the future ?

can some one please explain to me if the type of fuel specially deisel engine trucks is different b/n Euro 2,3 & 4?

thanks

can some one please explain to me if the type of fuel specially deisel engine trucks take is different b/n Euro 2,3 & 4?

thanks