agree! 4-stroke is much better than 2-stroke engine to the Earth!
that's why when I was looking for 50cc scooter, I only pick kymco easy for its 4-stroke engine. even it's more $ than other 2-stroke ones by other makers.

if environment bureau can have reward to anyone provides pollution vehicle photos, say $100, then use photos to fine those owners!!! maybe this action can get rid of those pollution sources quicker!!!