Under-recovery or the difference between retail price and its imported cost on diesel was 8 paisa per litre in the first half of September.
The under-recovery in the second half has turned into over-recovery or profit of 35 paisa per litre.
"Naturally, when there is an over-recovery or profit, rates should have been cut but oil companies are holding the price line as they await a clear decision from the government on diesel price deregulation," an official said.
This would have been first reduction in diesel rates in over five years.
Diesel rates were last cut on January 29, 2009 when they were reduced by Rs 2 a litre to Rs 30.86.
Since then rates have only increased as international oil prices climbed.
Since January 2013, diesel prices have been raised by up to 50 paisa a litre every month to eliminate under-recoveries.
The official said Oil Minister Dharmendra Pradhan is in Vietnam on an official tour and a deregulation or freeing of the fuel pricing from government control will be discussed upon his return.
Deregulation would give oil companies powers to change rates in tandem with cost like they do in case of petrol since June 2010.
Like diesel, state-owned oil companies have also not changed petrol rates which warranted a 54 paisa increase as its benchmark gasoline rates had firmed up in international market.
"There are elections in Maharasthra and Haryana and an increase now would not have been a very popular decision," the official said.
This is perhaps the first time that retail prices in India are higher than global rates.
A government statement on fortnightly under-recoveries stated that diesel under-recovery has been wiped out and there is over-recovery of Rs 0.35 per litre with effect from September 16.
Oil companies calculate the desired retail selling price of petrol and diesel on 1st and 16th of every month based on average international benchmark price and rupee-dollar
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