ICOMOS, the UNESCO advisory body, has asked Chiang Mai for 19 more documents on technical and historical matters, including building control plans for the old city and the ancient water system from Doi Suthep. Answers are due by 27 October 2026. No further site visits are planned, so the decision will rest on paperwork. For a Chiang Mai business, the practical effect is limited for now: possible future building-height or construction rules in the old city and buffer zones, which would affect property, renovation and tourism-related projects if the listing goes ahead.