What is the specific correspondence between English IELTS scores 1-9 and European standards A1-C2?

European standard A1 is equivalent to IELTS 1-1.5, A2 is equivalent to IELTS 2-3, B1 is equivalent to IELTS 3.5-4.5, B2 is equivalent to IELTS 5-6.5, C1 is equivalent to IELTS 7-7.5, C2 Equivalent to 8-9. \r\n"Common European Framework of Reference for Languages" CEFR. This set of standards carefully provides a benchmark for European language assessment structures and teaching guidelines, examinations, teaching materials, etc. European language reference standards are divided into c2, c1, b2, b1.a2.a1***6 standards. \r\nIELTS, the foreign name is International English Language Testing System, is jointly managed by the Foreign Language Examination Department of Cambridge University Examinations Board, the British Council and IDP Education Group. An English proficiency test set by people who study, work or settle in English-speaking countries. \r\nThe IELTS test is divided into two categories: academic and training, which are respectively aimed at students applying to study abroad and those who plan to work or immigrate in English-speaking countries. The test is divided into four parts: listening, speaking, reading and writing, with a total score of 9 points.