Question: why azo dyes are banned?
Answer: Under certain conditions, azo colourants can undergo a cleavage of the “-N=N-” azo bond to form “–NH2” group or an “Amino” group. Such a compound is called an amine. Some amines are carcinogenic in nature i.e. they can cause cancer and hence there is a ban on usage of dyes and pigments that can release such amines.