[@December][@AllHollowsEve] Amon was using chi-blocking principles applied through bloodbending (which hopefully is a forgotten art). So I'd assume he was applying the necessary pressure to chi points with the person's own blood. The lion turtles directly manipulated chi, so the healing (Korra's cure for Amon's technique) was likely strengthening the natural healing process.

You're very likely to see more environmentally friendly technology when the environment can physically and loudly object. I reckon the cars would still be internal combustion, but likely our level or better of hybrid car rather than the 80s dirty cars.