ITC is planning to invest Rs 2,500 crore during the next two-three years to put up a greenfield elemental chlorine-free (ECF) paper plant, which would increase its annual paper and paperboard manufacturing capacity to 5.5 lakh tonne."We are in the final stages of negotiations for the ECF project, and are looking at possible sites in Andhra Pradesh, Gujarat and Maharashtra," Pradeep Dhobale, chief executive of ITC's paper division, said.The final decision regarding the location of the two lakh tonne plant would be taken in a month's time, he added."The plant would be developed as an integrated pulp and paper mill with an investment of Rs 2,500 crore to be spent over next two-three years," he said.