The company announced that it will be launching a new series of eco-friendly products, which aimed to reduce plastic waste by 50%.

The correct phrase is "which aim to reduce plastic waste" because the relative pronoun "which" refers to the "new series of eco-friendly products" and needs to be followed by the base form of the verb aim. Similarly, "aim to" is the correct expression for indicating the goal or intention to achieve something. The sentence should be in the present tense to match the future action announced by the company, so the correct form is "aim to reduce" rather than "aim for reducing" or other variations. hence, the correct sentence will be- The company announced that it will be launching a new series of eco-friendly products, which aim to reduce plastic waste by 50%.