1. Fetched 1,081 kB in 23s (46.2 kB/s)
  2. Reading package lists... Done
  3. E: Failed to fetch http://ftp.iitm.ac.in/ubuntu/dists/xenial-updates/universe/binary-amd64/by-hash/SHA256/2d8d4ec37e1703bc9a4db6478ded72d626ec1476fcccdb4c8d93ff6b48a53f28 Hash Sum mismatch
  4. E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/universe/binary-amd64/by-hash/SHA256/ef29da028a8d49e26d35d670d59afa7b2fb4cb4a4a9b75d6fbdfdb56d357ee4e Hash Sum mismatch
  5. E: Some index files failed to download. They have been ignored, or old ones used instead.