India plans to slash tariffs on cars imported from the European Union to 40% from as high as 110%, sources said, in the biggest opening yet of the country’s vast market as the two sides close in on a free trade pact that could come as early as Tuesday.

Prime Minister Narendra Modi’s government has agreed to immediately reduce the tax on a limited number of cars from the 27-nation bloc with an import price of more than 15,000 euros ($17,739), two sources briefed on the talks told Reuters.

This will be further lowered to 10% over time, they added, easing access to the Indian market for European automakers such as Volkswagen, Mercedes-Benz and BMW.

The sources declined to be identified as the talks are confidential and could be subject to last-minute changes. India’s commerce ministry and the European Commission declined to comment.

India and the EU are expected to announce on Tuesday the conclusion of protracted negotiations for the free trade pact, after which the two sides will finalise the details and ratify what is being called “the mother of all deals.