DNA Special: Why is Indian Air Force still flying obsolete MiG-21 aircraft?

At present, the Indian Air Force uses the updated version of MiG 21, MiG 21 Bison. All MiG-21 aircraft will be retired from IAF by 2025.

DNA Special: Why is Indian Air Force still flying obsolete MiG-21 aircraft?
At present, the Indian Air Force uses the updated version of MiG 21, MiG 21 Bison. All MiG-21 aircraft will be retired from IAF by 2025.