Single parent - definition

Do not plunge yourself into technical definitions of "single parent" and do not look into wikipedia or Oxfor dictionary etc.  She is not a single parent without having a valid divorce from you and without your voluntary surrendering your right to have custody and visitation rights of the child.  If the passport authorities had granted passport without your "no objection" statement, they are wrong and you can take them to task by filing a writ  petition in HC after obtaining necessary documents from passport authorities.  You should also file custody case along with visitation rights in the competent court to get custody and in the meantime visitation rights.  Your rights are, on  the basis of your query, infringed and you should take remedial steps.