``Once brand names are declared as being adulteration free, we can determine how soon we can lift the blanket ban on sale of mustard oil,'' he said.

Within the 10-day deadline, ``the expert committee would advise retailers how they could check whether the mustard oil that they are selling is unadulterated. The experts would also set standards for quality control and dwell into the causative aspects of dropsy,'' he said.

``Even sweet-vendors have to have a way of testing the oil that they use,'' the Lt Governor said. ``If argemone seeds constituted five to 10 per cent of the mustard oil samples that were tested, it could not have been the handiwork of petty adulterators. Such high presence of argemone points to a design to kill,'' Kapoor told Express Newsline during the exclusive interview.

Kapoor says that experts have failed to determine the quantity of argemone that was mixed with the offending mustard oil. ``All that the experts have said so far is that some samples were `highly positive' and others were `simply positive.' But they have been unable to tell us the exact quantity of argemone seeds present in the mustard oil.'' Kapoor also discounted claim made by Delhi government representatives (without naming them) that 30 per cent concentration of argemone was found in some samples. Significantly, Delhi Health Minister Dr Harshvardhan had publicly stated that 30 per cent argemone was detected in some samples.

``This is not true. We had called experts from Lucknow Toxicological Survey Institute to quantify the argemone found in some of the samples. They failed to arrive at a figure. Then the Shri Ram Laboratory at Minto Road was given the task. Even they could not tell us the exact quantity. I think that the determination of exact quantity of argemone is the key to the question of causality. We also need to determine how much argemone in cooking oil is fatal,'' he said.

``I have talked to the Home Minister about the lack of quantitative results of sample tests. I am happy that the case has been handed over to the CBI. Anyway, it is not just a Delhi problem, because trade and agriculture transcend all boundaries,'' he said.

On why there were no powers of quality control vested with the PFA department, Kapoor said, ``There is, as such, no need for separate quality control measures.'' Delhi and Lakshwadeep alone have no licensing based on the criterion of quality control in the country.