As a child growing up in 1970s USA, I remember the vast amount of trash along our roads, city streets, parks and beaches. It was fairly common to see people throw trash out of their car windows.

What changed? I have never studied this, but I know we implemented large scale clean up projects, passed new laws and made a cultural shift in attitudes.

What changed was the environmentalism movement, usually symbolized by the crying Indian commercial.

https://tvtropes.org/pmwiki/pmwiki.php/Main/CryingIndian

>>>> My guess is it will take another generation for people there to appreciate how blessed they are to live in such surroundings but by then it will unfortunately be too late.

This in the parent comment is strange. It wasn't too late everywhere else, and it obviously won't be too late in Vietnam either. A clean environment is a luxury you can afford when you're rich. Poor places are dirty, but it's not like they can't be cleaned.

Yes, I was a kid in the 1970s and the anti-littering campaign was pervasive. I was too young to remember/notice the litter itself, but definitely remember the "Crying Indian" commercial, Woodsy Owl[1], and others. You always saw these in the Saturday morning cartoons, in particular.

[1] https://en.wikipedia.org/wiki/Woodsy_Owl

Yes, I should have included the rise of the environmental movement. And I came very close to including the crying American Indian ad, it was very impactful on me.

I also remember Sweden being like this until early/mid 90s. The only real change AFAIK was peoples' attitudes, as a result of government campaigns.

Hell, in the 60s you could watch wonderfully informational movies as this on the one and only available TV station https://www.youtube.com/watch?v=XrcrX9Qaw2o. (skip to 1:15 for the recommended practise of waste removal near the ocean).

Same in Germany. I remember piles of trash at almost every Autobahn stop and people burning piles of trash was normal. I think the willingness to keep the country clean is connected to prosperity. Only when the basic needs are met people care about the environment.

I can think of a few reasons:

- Convenience & economic: one kg of nylon bag costs around 2$, 20~40 times cheaper than biodegradable plastic, and nylon bag are taxed at more than 100%.

- Local market are full of farmers selling their fresh vegetables, poultry or pork. So when I go buy food for my dinner I come back with 3~5 bags, with each ingredients having their own bag. While a visit to supermarket often result in 1 bag for all of those.

- Average Vietnamese simply wasn't taught how precious nature is. Just 30 years ago we were riding on wood gas truck or cars modded to run on kerosene mixed with gasoline. There is a saying "Prosperity brings respect" (roughly translated) in Vietnam, and we are still poor and too busy to make more money.

- We simply don't have the facility for classifying trash and recycling/burning them.

How do you keep your meat and vegetables in a single bag? It's not impossible to reject bags in the local markets - I do that all the time. But on my travels around SEA but specially Vietnam, I feel tired and hopeless. I saw a lady from a toy shop throw a few batteries away to the curb without giving it a thought.

As an outsider, If I had to guess it would be lack of proper institutionalized waste management; one that’s not rigorously enforced.

In the West in the early 20th century we also had burning heaps of trash in abandoned or empty lots.

> Why do people just not think twice about throwing their waste in a ditch or a river or leave their picnic at the beach?

I think there are two main reasons. First, many people don't have environmental awareness. They weren't taught. That's not to blame them, but it's just a fact. However the new generations are indeed educated on that subject. We were taught to not litter, to pick up the trash, etc. But this is where the second issue lies: when we don't follow the rules, nothing happens. No immediate consequences. Whereas in other developed countries, when people break the rules, they get fined, they get other people looking at them funny. That collective awareness helps enforce the simple rules.