For me, when thinking about places that are good for the environment, I really think Japan and South Korea should be thought of.
Japan has beautiful nature, and they have worked a lot on making travel there sustainable. In the Northern Japan Alps, locations such as Kamikochi provide stunning sceneries and accommodations that are kind to the environment. The public transport in the country is very good, with trains and buses allowing for travel that does not harm nature too much.
While I stayed in Seoul, the city's commitment to keeping nature was very impressive. They have good systems for handling waste and lots of parks with greenery, such as Namsan Park, which shows they care a lot about maintaining their environmental charm. A special part of my journey was going to Bukhansan National Park, where I went for a hike that I won't forget. The area had many trees and beautiful views all around. It impressed me how the park is looked after in a way that it does not harm nature much but still lets people enjoy being outside in the natural world.
When I was in Busan, I got the chance to go see Haedong Yonggungsa Temple. It really stayed with me. The building of the temple is amazing, and they care a lot about keeping nature safe and using resources wisely. The sea and cliffs were very peaceful, like a quiet place that cares for nature. If you want to visit Busan, I recommend this guide https://gowithguide.com/korea/busan They have custom tours in Busan where you can see how the city works with nature and understand its culture and past. Their local guides can offer useful advice and suggestions for how to travel responsibly.
To sum up, Japan and South Korea both have amazing places that are good for the environment. These spots mix beautiful nature with ways to keep it safe. If you visit Japan's green areas or South Korea's lively towns, you'll find many chances for travel that doesn't harm the earth.