CBI, probing the 2G spectrum scam , has reminded telecom regulator TRAI to ascertain the exact loss to the government owing to allocation of spectrum to all operators between 2001 and 2008 following varying estimates.

The estimates varied between Rs 35,000 crore and Rs 1.76 lakh crore.

CBI sources said today a reminder was sent to TRAI as there was no word from the regulator ever since the investigating agency first made its request in January this year.

Based on the findings of the CVC , the CBI had estimated in its FIR in 2009 that the government may have lost over Rs 22,000 crore due to irregularities in the allocation of spectrum in January 2008 by former Telecom Minister A Raja, who was arrested in February on charges of favouring some private firms.

Later, the investigating agency had estimated the loss to be at around Rs 35,000 crore. The loss was less than the figures arrived at by the Comptroller and Auditor General (CAG) which had pegged the notional loss to Rs 1.76 lakh crore.

The agency''s decision to approach TRAI was taken in view of the varying estimates of the losses to the exchequer on account of the sale of spectrum in 2008.

The CBI had requested the TRAI to set up an expert team which will go into the entire gamut of spectrum pricing and give an estimated loss which can be proved in the court.

However, it has been six months since the agency has heard from the telecom regulator, prompting the CBI to send in a reminder ahead of the next date of hearing in Supreme Court on July seven.