Universities will consider the CBSE as equivalent to GCSEs in terms of general education, but I think what they might mean is that they need a specific English Language qualification, which CBSE generally isn't one of. Your options then are to take a specific English Language qualification - they'll obviously take a GCSE or an iGCSE in English Language, but many will take a range of other qualifications - I'd recommend looking at the IELTS, most places will accept that, there are test centres all over the world, and basically it is exam-only so it's a lot more convenient than something like GCSE. As well as the IELTS, the TOEFL and Pearson PTE Academic are also commonly taken.