Some catastrophe like Chernobyl only bigger could turn people away from technology (this is sort of the lines my game world is on). Technology blamed for the downfall of society and thus frowned upon.

Making it illegal to pollute the environment would cause totally different technologies to be invented because most of what we have today causes pollution.

If you look at the technology we have today most of the big items come from war. <-- sad comment about mankind. Afterwards they tend to come up with civilian uses. A peaceful world that did not go in for killing one another would follow a different technological branch than what earth has taken. Not that what we can do today wouldn't be possible but it would probably be shut down for being a crime.

If you were immortal and concerned for the beauty of your environment and were against war you might spend decades in design of something new that not only would do what you wanted but would also work harmoniously with the world you lived in. Just because you could do something wouldn't mean it was the right way to do it. Thus, time would be spent in making sure it was safe and non-toxic, yadda, yadda, yadda. Short lifespans and greed have created strip mining and drilling into Ocean floors with little preparation on what to do if it backfires (to point to an obvious recent disaster) as well as many other so called advances that have serious side effects. I always think of Thalidomide as the perfect example of technology gone wrong. If you never heard of it, you are probably too young to remember it but look it up, it's pretty bad medicine.

Have to run to work now but if I think of more I will post.

Good thread, I like thinking about how things might be done differently and what it would be like if it were. Where would we be if the library of Alexandria had not been lost or some of the civilizations in history that were destroyed along with their secrets. Might our world be an entirely different place?