TAN requirement: existing TAN may be used for tax collection at source; otherwise apply using Form 49B. If a TAN has already been allotted for tax deduction at source, the same TAN is to be quoted for tax collection at source in all returns, challans and certificates and no separate application is needed. If no TAN has been allotted, an applicant must submit the prescribed Form 49B with the application fee at any TIN Facilitation Centre to obtain a TAN for collection at source.