Learn Italian: Tutta la plastica, la ricicliamo qui. - All the plastic, we recycle it here.

This is called left dislocation. When you move the object (tutta la plastica) to the very beginning of the sentence to make it the main topic, Italian requires you to refer back to it with a matching pronoun. Since plastica is feminine singular, we use the direct object pronoun la right before the verb.

Is it grammatically correct to just say Ricicliamo tutta la plastica qui?

Yes, that is the standard, neutral word order. However, moving tutta la plastica to the front changes the focus, translating roughly to 'As for all the plastic, we recycle it here.' Once you move the object to the front like this, inserting that extra la becomes mandatory in Italian.

Why do we need the article la in Tutta la plastica?

In Italian, when tutto (or its forms like tutta, tutti, tutte) means 'all of the' or 'the whole,' it must be followed by a definite article. If you just said tutta plastica, it would mean something is made 'entirely of plastic' rather than referring to 'all of the plastic' you have to recycle.

How would this sentence change if we were talking about glass (il vetro) instead of plastic?