I lived in Taiwan for 2 years. This makes me both sad and hopeful. Hopeful because that island REALLY needs to focus on pollution. It's a country whose economy is built around manufacturing, and the factories dump tons of emissions into the air. I had a necktie I would show people when I came home. It was a nice charcoal grey tie. I'd then show them the back of the tie (the part that spent its life against my body, less exposed to the air), and it was royal blue. Bags and cups obviously don't contribute to air pollution, but the incense they mentioned definitely can (everything is extremely hazy during Ghost Month), and there is generally a lot of pollution of all forms, which you expect in such a densely populated area.
On the flip side, I loved the street vendors that served drinks. They would make your drink, pour it into a 700cc plastic cup, then use a head press to melt a thin plastic lid to it (think slightly thicker Saran Wrap). You could throw 5 or 6 of them in a plastic bag and not worry about them spilling. When you are ready to drink it, jab the disposable plastic straw through the lid and drink up. It was a genius system, and I will miss it dearly. I don't know what will become of those drink stands (seriously one every other corner throughout every city I lived in).