Canadian Green Bond is pretty new. I have not seen anyone reporting interest on it yet. Tax exempted? I am not sure.
HK Green bond? I don't see why Canada will give tax exemption to green bond not issued by Canada.
https://www.canada.ca/en/department-finance/news/2022/03/canada-issues-inaugural-green-bond.html
https://www.cpacanada.ca/en/news/canada/green-bonds-explainer