What is the fine-grained topic of the following text: Paul has been active in sustainable development of Hong Kong through organizations such as the Designing Hong Kong, Society for Protection of the Harbour, Coalition on Sustainable Tourism, Heritage Watch, Save The Street Market, Conservancy Association, ProCommons, Business Environment Council, Harbour Business Forum, Clear the Air, and others. Only return the topic.
Paul's involvement in sustainable development in Hong Kong through various organizations.