Question 074: I had bought clothing that was most likely made by Hindus in India. Do I have to wash it, before I can wear it? What is the Rules concerning the impurity of clothes made by hindu ?
Answer 074: A well-known religious law says: “Everything is ritually pure for you unless you come to know that it is ritually impure.” This law declares everything to be pure unless one becomes sure a particular item has become impure. And as long as you are not sure that it has become ritually impure (najis), it is to be considered pure and you can apply all the rules of purity to it without any hesitation or doubt.[1]
Therefore, according to the above mentioned rules, there is no need to wash the clothing if you are not sure whether or not it has become ritually impure (najas). Otherwise, if you come to know that the clothing has become impure you are supposed to wash it.
For further information in this regards, please refer to the following answer:
Index: Permissibility of using Henna even if it was mixed by a Hindu, answer 563.
[1] . The official website of the office of Sayyid Sistani (ha), Q&A: Najasat.