1 ~ (I don't know)
2 ~ Because people litter a lot and just waste their things and don't use it usually. Which harms the environment. (The main sources for solid wastes are domestic, commercial, industrial, municipal, and agricultural wastes. The increase in the quantity of solid waste is due to overpopulation, affluence, and technological advancement.)
3 ~ (I don't know again T^T)
4 ~ Donate Clothes. ...Reduce Food Waste. ...Eat Healthy. ...Save Leftovers for Next Day. ...Buy Things With Less Packaging. ...Boycott Plastic Water Bottles. ...Just Don't Buy as Much Stuff….Really. ...Recycle.
That's all! :3 Hope this helps!~ (Sorry I couldn't help with 1 and 3. I Tried and I took a long time writing this.)