Lots of issues raised in your comment, ยายธี:

1) Thailand has been a crossroad for thousands of years -multicultural is deep-rooted-;

2) mostly organic acids (formic กรดมด, acetic น้ำส้ม,... น้ำหมักชีวภาพ) are used these days (sulphuric acid was used before this). These acids can harm skins but not really toxic and break-down quite quickly

3) burning rubbish in backyards (no bigger than 1mx2m piles) will be a fact of rural life. It costs a match or two - much cheaper than disposal by other methods. However, burning many plastics can produce smelly toxic fumes harmful to people and trees.

4) Yes! We have to 'change' our ways to make living 'in high density' bearable. And that is one 21C issue for Thailand (people and government) to face.

5) Were you still around Karnchanaburi or down South down (when you took that picture)? I ask just to gauge the extent of rubber work ;-)