WITH NEAREST sub
jitendra@jitendra-Aspire-S3-391[test] perl testMAT.pl mat.txt         [10:17PM]
nearest to 37 in array is: 35  and name is china1
nearest to 35 in array is: 37  and name is china1
nearest to 59 in array is: 48  and name is africa1
nearest to 70 in array is: 30  and name is africa3

WITH use List::Util 'max' 
jitendra@jitendra-Aspire-S3-391[test] perl testMAT.pl mat.txt         [10:19PM]
nearest to 37 in array is: 35  and name is china1
nearest to 35 in array is: 33  and name is china2
nearest to 59 in array is: 56  and name is usa1
nearest to 70 in array is: 30  and name is africa3