When I was reading the paper, I came across this passage, "Around 2000, international investment arbitral tribunals began to pay attention to the public interest issues involved in such cases, and in contrast to the public purpose of the host country's regulatory measures, which had previously been virtually ignored, tribunals began to apply the principle of sustainability to cases during this period, re-examining the imbalance between the public and the private interests that existed in international investment arbitration. " It would be interesting to know how this conclusion was reached.