My favourite thing I saw in Mexico regarding sustainability was creative upcycling: beer or spirit bottles were made into ice cream glasses.
There were glass bottle returning schemes – in which shop owners would be financially rewarded for returning soda bottles to be refilled – many signs saying “sin popote” (translation: without straws) and supermarkets packing groceries into old cardboard crates rather than plastic bags. Whilst all of these may seem like small actions, collectively they will have saved a significant amount of plastic waste. When diving the reefs for multiple days, it was one of the only times when I didn’t have to pick up plastic from the seafloor.