I enjoy travelling light but it should not come at the cost of environment bearing the brunt for the sake of my convenience.
To avoid this, I have added the following items to my list:
1) Reusable Water bottle: Instead of buying plastic water bottles, carry one that you can refill. Tap water is drinkable in many countries, so you can fill your water bottles from the kitchen sink. I usually ask my hosts or the hotel staff in India, and most of them gladly oblige.
Did you know that many developed countries send away their used plastic water bottles to landfills in developing countries?
2) Lunch box: I realized that I purchased a lot of street food, served in disposable plastic cups and plates, or packed in polythene or styrofoam containers for take away. To avoid creating unnecessary trash, I now travel with this lunch box.
3) Flask: To avoid disposable cups for drinks, I bought this thermos flask. It keeps the contents hot or cold for the longest time.
Did you know that paper coffee cups are disposable only if the thin plastic sheet lining can first be removed from them?
4) Reusable tea bag/kettle with a strainer: Tea bags are disposable, and wrapped individually in plastic covers. I have decreased the consumption of tea as production of tea is an resource intensive process. I hope to switch entirely to herbal drinks eventually but as of now I have switched to using a kettle with strainer. You can also get a reusable tea bag.
5) Straw: I got reusable silicon straws. I used them on my beach trip to drink coconut water without any guilt. They come in a small pouch with a cleaning brush.
Disclaimer: None of the products in pictures are sponsored.