What does the number(within triangle recycle logo) on plastic bottle or cover mean?

It was a work from home day for me, and it was after noon lengthy call and my presence required was least, so left with option - be on mute; I leave it your imagination to guess how WFH productive would it be especially post lunch! as usual look over thing on the table..rolling the water bottle...come across the glancing the description found on bottle bottom... recycle icon(triangular chasing arrows).. that's where I become attentive of googling about that...

Have you ever wondered of small triangle & a number within, mainly located on the bottom of plastic container or bottle, luckily cover doesn't have one! I meant bottom not the number, hence easily noticeable. Need not to worry even if we haven't as the purpose of it is for composite identity & recyclable nature. In other words,

• How to recycle that specific plastic
• How toxic that plastic is
• What should be or not be inside that container,

which is really bigger picture, still pretty table at the bottom here may give kick start, if interested. With the intent of day to day consumption basis, let me touch base 3rd point(Health) and leave the rest(environmental) for your interest.

and the term BPA?... I'm sure you have heard.... developed cities takes about it much nowadays!
Plastic water bottles are made from polyethylene terephthalate. For either of the reason below, it could releases the toxic chemicals antimony and bisphenol A, commonly called BPA. Which is off-course harmful, BUT depends on the level it get mixed and I'd not flag as 1 category and confuse here.

Acceptable we do can't gave up, but try let's compromise with time/money rather health. With that said, just 2 thing to note.

1. One Time Use - #1 mostly found on water bottles which can't be avoided and it's safe too unless kept in high temperature.

2. Re-Use(Reduce Reuse) - Going with #5 or "PP"(Poly Propylene) printed ones, when it comes to re-use as both safe, and very economical to use with the only caveat being that it may not be as pretty and clear/transparent as your PET bottle.

FYI -