rm -rf /etc/yum.repos.d/*

cat << 'EOF' > /etc/yum.repos.d/base.repo
#https://vault.centos.org/centos/6/
EOF

cat << 'EOF' > /etc/yum.repos.d/epel.repo
#https://archives.fedoraproject.org/pub/archive/epel/6/
EOF

yum clean all
yum makecache