As per the Kurkure plastic rumor, when you burn Kurkure it melts. Definitely, when you burn Kurkure, Kurkure melts. The reason why Kurkure melts is because Kurkure contains carbohydrate in the form of corn starch. When any carbohydrate snack (like gol gappas, matharees and namkeens) is burnt, it burns the same way like Kurkure burns. But that does not mean that those snacks contain plastic.
AIIMS has also issued a letter saying that they have not issued any such chain mails