According to the agency four locations in Chennai and two in Kolkata are being searched since early morning.
The premises of one S Kailasam at Tenaympet have been raided in Chennai. Mr Kailasam is the maternal uncle of P Chidambaram's son Karti Chidambaram, sources said.
In addition, the premises of S Sambamoorthy and Ramji Natarajan in Chennai and that of Manoj Mohanka at Lee road and Lovelock Place have been raided by the ED.
The raids are in connection with the ED probe into the Foreign Investment Promotion Board (FIPB) clearance given to the Aircel-Maxis deal in 2006. The agency had said it is investigating "the circumstances of the said FIPB approval granted by the then finance minister P Chidambaram".
The ED also alleged that Karti Chidambaram has "disposed" of a property in Gurgaon, which he had allegedly rented out to a multinational company "to whom foreign direct investment (FDI) approval had been granted in 2013".
It charged that Mr Karti had "also closed certain bank accounts and attempted to close other bank accounts in order to frustrate the process of attachment" under the PMLA.
The agency said FIPB approval in the Aircel-Maxis FDI case was granted in March, 2006 by the then finance minister even though he was competent to accord approval on project proposals only up to Rs. 600 crore and beyond that it required the approval of the Cabinet Committee on Economic Affairs (CCEA).
"In the instant case, the approval for FDI of 800 million USD (over Rs. 3,500 crore) was sought. Hence, CCEA was competent to grant approval. However, approval was not obtained from CCEA," it alleged.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)