Sorry to say but recycling numbers are a bit of a con.
That symbol of “chasing arrows” you find on plastic does NOT mean it can be recycled.
What we often call “recycling numbers” are actually “resin identification numbers” - meaning they tell you what kind of plastic you are dealing with. Whether a type of plastic can be recycled or not depends on the technology available in the local area and whether it is economically feasible to do so.
So why use a recycling symbol for these numbers as opposed to, say, a circle?
This is an intentional deception and is part of the dark history of the plastic industry. This is a very American story so why not listen to an American explain it:
Don't be alarmed by the video title. Recycling is a "scam" because it is misleading, not because it doesn't exist.
In the 1970s and 80s, as public concern about plastic pollution grew in the US, the industry responded by heavily promoting recycling. The idea was to convince people that they could continue using plastic without feeling guilty, because recycling would supposedly prevent their waste from having a negative impact on the environment.
The misleading “chasing arrows” were part of these marketing tactics.
In reality, plastic is difficult to recycle and it's often cheaper to make new plastic than to recycle the old stuff.
While there is some plastic recycling, it's not as widespread as you might think. Types #1 and #2 (PET and HDPE) have relatively high recycling rates (around 20-30% globally), and #5 (Polypropylene) is also recycled (~3-5%), especially when it's industrial waste.
The other types are technically recyclable, but it's usually not commercially viable to do so.
The government has set up a system for collecting recyclable plastics, but whether they actually get recycled is a commercial decision.
In other words, blame the markets for not recycling them. And blame big plastic for making you think that those numbers meant the material is recyclable.
tl;dr: just never call these “recycling numbers” again.