Over a year into the exercise, German auto major Volkswagen has been able to rectify only 30 per cent of the 3.4 lakh recalled diesel vehicles it had equipped with defeat device that helped cheat emission tests in India.
Volkswagen Group India said the process has been delayed as it involves different brands, engines and models.
The company's headquarter has so far given approval for engine updates that cover almost 70 per cent of the vehicles which have been recalled in India.
Overall, by the end of last month, 30 per cent of the entire lot of vehicles that is eligible for the update has been covered, a Volkswagen Group India Spokesperson told PTI.
In December 2015, the group had announced recall of 3.4 lakh vehicles in India across its different brands, including Audi, Volkswagen and Skoda, sold from 2008 till end of November 2015.
A government-ordered probe had found the automaker's EA 189 diesel engines were equipped with a defeat device that helped it cheat on emission tests.
The company last year announced plans to update the engines of the recalled vehicles.
On the slow progress of update, the spokesperson said several brands, various markets and models, different engine variants and gearboxes and various model years had to be considered while developing the updates.
The technical measures were being defined and developed by Volkswagen Group at the headquarters in Germany.
"Once they were approved by the authorities in Germany, these updates were tested by the Indian authorities. All of this has been a lengthy process and that caused a delay," the spokesperson added.
The updates are tested by ARAI and only after their approval are they rolled out to customers.
Final two approvals for updates are currently in the pipeline and are expected to be received in the next few days. These would correspond to the remaining 30 per cent of the volume of cars, the spokesperson said.
For models produced and sold in India after December 2015, the updates have been implemented during production as soon as they were approved by ARAI.
"The models between December 2015 and till the updates were approved by ARAI and are a part of the voluntary recall process," the spokesperson added.
Volkswagen has admitted use of defeat device in over 11 million diesel engine cars sold in the US, Europe and other global markets that allowed manipulation of emission tests by changing performance of vehicles to improve results.
As per latest reports, a federal judge in Detroit has ordered the German car maker to pay USD 2.8 billion criminal penalty negotiated as part of a settlement with the US Justice Department last January.
With this, the company is likely to shell out a total of around USD 30 billion, which also includes price of buying back almost 5 lakh vehicles sold in the US.