AIADMK General Secretary Jayalalitha urged the Prime Minister Manmohan Singh on tuesday to order a CBI inquiry into 'large scale corruption' in Karaikal based Chemical companies that has allegedly involved in smuggling potash that was to be supplied at concessional rates to farmers. In her letter to the PM she suggested that the surprise inspection by the Agricultural Revenue Department of the Puducherry government, came out with the finding that Vaigai Chemical Industries and Karaikal Chocolates possessed stocks beyond their production capacity. This had led to a suspicion vis-a-vis the source of supply of potash.