S. 206C : Collection at source – Trading -Limitation-Order passed beyond limit of four years is bad in law -Though Section does not impose any limitation period for the AO to hold the assessee to be in default for collection of tax at source, a reasonable time limit of four years has to be read into the statute- Orders passed after this period are beyond the limitation and are void-The fact that the Dept became aware of the default later is irrelevant. The fact that the assessee admitted his liability is also irrelevant- Assessment is held to be bad in law .[ S.191, 201 ]