In yesterday's lesson I mentioned that someone asked me this question: "Can we use the passive in writing task 1?"
If you ask a question like this, it tells me that you're focusing on the wrong thing. Your method, or your whole approach to the IELTS test is wrong.
When you look at a graph or chart in writing task 1, you shouldn't be thinking, "can I use the passive to describe this information?". You should be thinking, "what is the main trend, which numbers should I compare or contrast, how will I paraphrase the question etc.?".
Don't take a 'grammar approach' to your IELTS preparation. Take a 'task response' approach: focus on answering the question.